With Rob Manfred taking over as MLB commissioner on January 25th, we’ve seen a steady stream of news articles suggesting ways he can immediately improve the game. Some ideas involve limiting the amount of relief pitchers each manager can use in a single game, or forcing relievers to face more than one batter—perhaps more than two batters. The logic is that these changes would quicken the game and produce more offense. I don’t intend to debate whether or not MLB should implement these changes, but I can say the logic is sound. Obviously, fewer mid-inning pitching changes would accelerate the game, or at least eliminate some downtime. Though, ascertaining exactly why fewer relievers would amount to increased offense takes a little more research.

The basic premise is that runs have declined because managers are using more relievers to take advantage of handedness matchups, and because relievers are better than they’ve ever been. A quick search of fangraphs.com reveals that mangers are going to their bullpen more often. In the 1990 season, relievers made 8483 appearances. That number has increased steadily to 14,459 in 2014. The number of innings thrown by relievers has increased from around 12,000 in 1990 to between 14,000 and 15,000 the last few years. It’s also evident from those numbers that the average length of a relief outing has decreased.

According to Patrick OKennedy of blessyouboys.com, the average number of relievers used by both teams in an MLB game was 6 in 2014, up from 2.8 in 1974. (Not surprisingly, games are lasting significantly longer than they did in 1970 as well.)

Ken Rosenthal points out that in 2013 and 2014, and presumably farther back than that, the average runs scored per half inning were lowest in the 7th through 9th innings. Rosenthal also says that relievers faced just one batter 8.7% of the time in the last five years, and they faced two or fewer batters in 16.4% of their appearances. So as you know if you’ve been watching baseball regularly the past few years, left-handed and right-handed specialists make frequent appearances.

Matt Eddy at Baseball America examines trends in bullpen specialization, with a particular emphasis on the success that left-handed pitchers have against lefty batters.  He shows that between 2011 and 2013 (and the trend continued in 2014) AVG and OBP were 30 points lower, SLG was 70 points lower and OPS was 100 points lower for lefty batters against LHP than against RHP. Right-handed hitters also faired significantly worse against RHP than they did against LHP.

Eddy talks about a shift in managers’ priorities over the last 20 years or so. In the past, managers tried to gain platoon advantages for their offense, having batters face opposite-handed pitchers 60% or more of the time. More recently, teams started keeping 12 pitchers, and managers started seeking platoon advantages for their pitching and defense, so batters now face opposite-handed pitchers 55% or less of the time.

Eddy includes graphs to show that right-handers strike out more than league average against RHP, but lefties strike out significantly more than that against LHP; also, ISO and AVG are lower than league average in righty vs. righty situations, and far lower than that in lefty vs. lefty situations.

In the second part of his article, Eddy goes on to say that plate appearances by all batters against LHP have increased steadily from 24.5% in 2002 to 28.5% in 2013, and lefty vs. lefty match-ups have gone from 6.8% to 8.6% of PA in that time. More left-handed relievers are making the majors based solely on their ability to retire left-handed batters, and teams encourage some LHP to find ways to improve their performance against left-handed batters, even if it diminishes their effectiveness against right-handed batters.

Some of the most telling data I’ve found is in this article by Jonah Keri and Neil Paine on fivethirtyeight.com. They have a graph to show that 50 years ago, on average, about 1.5 relievers were used to pitch 2.5 relief innings per game. In 50 years, the average number of relief innings pitched per game has only increased to about 3, but the number of relievers used per game has doubled to around 3. This is similar information to what I found on fangraphs.com about the growing number of relief appearances. Keri and Paine also show that the number of relievers throwing 95 mph or above has nearly quadrupled in the last 10 years, from about 3% of relievers to around 12%. Their last graph, I’m going to steal and put on our page.

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You can see that back in the late 60s and early 70s the OPS+ allowed by relievers was significantly higher than that allowed by starters. But since then, and especially in the last 20 to 25 years, OPS+ allowed by relievers has declined sharply, while OPS+ allowed by starters has increased slightly, creating a significant divergence between the two. As Keri and Paine assert in the title of their article, it does seem that bullpens have taken over baseball, or at least the last few innings of baseball. Fewer runs in the last 3 innings should equate to fewer runs overall.

Let’s look a bit more at the assertion that relievers are better than they’ve ever been. The strikeout rate has been rising for years (K/9 by relievers has increased from 7.30 to 8.46 in the last 10 years), but Dave Cameron questions whether that is directly correlated to an increase in fastball velocity. Relievers’ fastball velocity (FBv) has gone from 90.6 mph in 2002 to 92.5 in 2014. Cameron looks at the strikeout data by month and shows that batters typically strike out just as much in April when fastballs are slower, possibly discrediting the idea that faster fastballs lead to higher strikeouts. But, relievers are also throwing their sliders, curveballs and changeups significantly faster, which could have an impact on strikeouts. Furthermore, relievers have gone from throwing cut fastballs .5% of the time to 5.7% in the last ten years. It isn’t just Mariano Rivera getting people out with the cutter anymore.

This USA Today article from July 2014 discusses the effectiveness of the cutter, as well as the difficulty in recognizing it—not just for batters. Mark Melancon, the Pirates’ closer, says he throws a cutter 85% percent of the time, but fangraphs.com only has him down as throwing it 48% of the time. So, it’s possible that pitchers are throwing the cutter far more than the stats say. Jeff Sullivan argued last year that, with Rivera retired from the game, Kenley Jansen’s cutter was the new most dominant pitch in baseball–edging out Aroldis Chapman’s fastball.

However, starters have gone from throwing the cut fastball 1.3% of the time in 2004 to 6.4% in 2014, so there’s no current evidence that relievers are getting more people out with cutters than starters are. Still, there are injury risks associated with the cut fastball—apparently the Orioles and A’s discourage their young pitchers from throwing it–so in the future it could evolve into a pitch better suited for relievers that don’t throw as many pitches and don’t need as wide of a pitch repertoire.

Relief pitchers today are throwing the ball harder, they’re striking more batters out, they’re more likely to be facing a same-handed hitter, and they may only be charged with retiring one or two batters. Therefore, relievers’ overall success rate is higher and fewer runs are being scored in the later innings of games.

37 Responses

  1. Steve Mancuso

    Managers are using more LH-LH and RH-RH match-ups late in the game. Plus relievers are throwing harder than before (greater velocity improvement with relievers than starters). When you add those two factors together, that seems important in relation to run scoring. Nice post Jason.

  2. zaglamir

    This is so obvious now that you’ve pointed it out, but it’s something I’d have never thought of. That graph is so telling. Very interesting insight.

    However, I am curious that the OPS+ doesn’t show a rise for starting pitchers (more a bump up really) around 1999-2005, with a decline at the end of that time frame. The slow upward trend makes sense in terms of the “steroid era,” but the lack of a downturn in that data around the time that the runs/game ticked down (and the steroid era slowed down) seems strange to me. One would think OPS would be correlated quite closely with run production.

    • Jason Lawrence

      You’re right, that is interesting. Quickly looking at starters’ stats on fangraphs between ’92 and ’08, there aren’t any obvious trends jumping out at me, other than the strikeout rate creeping up.

    • Nick Doran

      OPS+ is relative to league average, so the total leaguewide OPS+ for each year in that graph has to remain at 100. If reliever OPS+ is going down, then by definition the starter OPS+ would have to go up.

      If you look at OPS rather than OPS+ you should see the trends you are looking for regarding the steroid era.

      • zaglamir

        I looked for those using the league average OPS over the course of the years, and it’s relatively constant. 1999 and 2000 are a bit outlier-ish at .780 (but even that is within 2-sigma)… every other year is within on standard deviation of the mean at .760. Really, I don’t see a spike in the data so much as a drop off in the past few years.

      • zaglamir

        Ahh, let me correct that. I hadn’t gone back far enough. Starting in 1993, the OPS jumps up by 70 points and stays there until 20 until 2011, when it comes back down to what it was in the 1980’s.

  3. gusnwally

    O don’t think handcuffing a manager is the way to go. Let him change pitchers as often as he feels necessary. However how about limiting the ridiculous number of warm up throws when he reaches the mound. He is already warmed up. How about 3 pitches to get the feel of the mound and let’s go.

    • jdx19

      I agree. There are better ways to shave time, like not allowing batters to walk 30 feet from the plate between pitches.

      • preacherj

        Full agreement. The core issue with limiting relief pitchers is time management, not runs scored, although the argument has merits. I believe time can be cut elsewhere, and anything that limits moves that a manager makes should be discouraged. I love watching the agony of a manager deciding whether to burn his last couple of relievers late. Many of these proposed rule changes are made in the interest of attracting more casual fans to the sport. While I appreciate the sentiment, I certainly don’t want anything enacted that affects the nuances of the game that more seasoned fans appreciate.


        Agree, of you limit the pitcher to 2 batters you would then be able to stack the lineup L, R,L, R and give the offense an undue advantage. I agree with a pitch clock but only if hitters cannot step out in them! Managers should be able to EITHER talk to the pitcher OR take them out. Mangers should tell the umpire from the dugout the pitcher will be taken out, no walking slow, talking, taking the ball and then calling for the reliever. If they walk out, they must finish that at bat.

        If there are too many rules, pitchers will start faking injuries so be careful!

    • Carl Sayre

      That was going to be my suggestion also. I would think that 3 pitches for the home pitcher and maybe 5 for the visiting pitcher.

  4. jdx19

    Good write-up, Jason! I’m just starting to come back from the off-season and I’m excited to have a bunch of new writers on board to help the stalwards like Steve and Jason!

    • jdx19

      I meant Jason Linden, above, as the *stalwart. My last post was full of fail. Shaking off the winter cobwebs!

      • Jason Lawrence

        Thanks a lot, I’m excited to be doing it. And I totally understood what you meant, no failure at all

  5. redmountain

    Rather than deal with the relievers, I would put in a pitch clock and limit the amount of times a hitter can step out, and how far they can go when they do step out.(Perhaps keeping one foot in the batters box.) This would effect the speed of the game, and might .effect run scoring positively or negatively. Has anyone done a study showing the time between pitches or half innings? If TV complains about commercial time, then have them start doing crawlers at the bottom of the screen or framing the screen with one advertiser each half inning. (This inning is brought to you by the King of Beers) A plus might be that we would hear less about JTM and more about the actual game.


      on JTM I totally agree (and Thom talking about UDF malts too -he must get a royalty). I would be OK with Skyline theme music in the backgroud.

    • VaRedsFan

      I’m with you, use a pitch clock, and the batter must keep a foot in the box. Experiment with these rules during spring training. Make it happen. Keep Bruce in the box.

  6. tct

    I think managers should be able to change pitchers how ever much they want. I don’t have a problem with that. What I do have a problem with is the stalling techniques they use to allow a guy in the bullpen to get ready.

    You see it quite a bit: a reliever comes in and can’t find the strike zone or is getting hit hard. The manager wants to bring him out, but the next guy in the bullpen isn’t ready yet. So, the manger sends his pitching coach out to buy as much time as possible. Then he has the pitcher step off the rubber a couple times or throw over to first if a runner is on to waste even more time until the next guy gets ready. It’s BS. The offense doesn’t get these advantages. Managers aren’t allowed to come out and talk to struggling hitters. Coaches aren’t allowed to stall for five minutes while a pinch hitter goes and takes some BP in the cage to get ready. Why allow the defense to do this?

    Eliminatine all visits to the mound by coaching staff except to change pitchers or check about an injury. Limit catchers to one visit per inning. Make a rule that a pitcher throwing over to first has to be making an attempt to pick the runner off. No more soft tossing between the mound and first base to waste time. The defense should pay a penalty for these situations.

    • lwblogger2

      I love this. There isn’t much a catcher needs to say that would take more than once visit, at least per batter. I also used to always tell my pitchers, if you throw over, make sure it’s with a purpose. The “calling card” throw overs very rarely work and sometimes when you soft-toss it over there, you actually run a higher risk of throwing it away. Granted, I wasn’t catching Major League players but I caught some really good players, some went on to play in the minors or Majors.

    • i71_Exile

      I don’t really like “intent” rules for obvious reasons—they require judgement—and we’d start to see a rash of feigned injuries. Pitchers/catchers can slow the game down in other ways by running through signs, shaking them off, running through more signs, requesting a new ball, digging dirt out of spikes, etc.

      I think we just need to embrace the pace of baseball. If MLB really wants to make baseball fit into a two or two and a half time window, they’d cut out the eight and ninth innings.

      • tct

        It’s not just a pace of game issue, though. It’s the fact that you’re allowing pitchers to have a huge advantage that hitters don’t get.

        Imagine this scenario: Reds up by one, bottom of the ninth, two outs, Chappy on the mound with an 0-2 count. The opposing hitting coach calls timeout, goes and talks to the hitter, reminding him of scouting reports, what Chapman likes to do when he’s ahead in the count, any mechanical things he’s noticed, any patterns or tipping of pitches that Chapman has fallen into, etc.. It may not help the hitter a lot, but it would probably help a little, right? If nothing else, it breaks Chapman’s rhythm and allows the hitter time to refocus.

        But we don’t allow hitters to have the luxury of speaking with their hitting coach during at bats. So why allow the pitchers to speak with their coach? Why allow a team with a struggling pitcher to stall while another gets warmed up?

        As for intent rules, I hear what you are saying and would usually agree with you. But generally, it’s pretty obvious when a pitcher is throwing over to first just to waste time or break the opponent’s concentration. When a pitcher lobs a ball over so slowly that my three year old son could catch it, he is not trying to pick anybody off. Make them at least make a legit pick off move and throw the ball with some life on it. This would make it more likely to be thrown away, so they would use pick off throws more sparingly. And really, this rule would be no more subjective than the balk rule or the strike zone.

      • i71_Exile

        Yeah, the “pick-off” lob is annoying, but if it were outlawed, we’d just see the pitcher use another tool to stall: the pick-off throw that’s a little faster or maybe the glare at first followed by a quick step off and then repeat of the signs from the catcher. 🙂

        The batter has weapons of his own to stall or break a pitcher’s rhythm so it’s not totally one-sided: the ubiquitous step out of the batter’s box, calling time to get “dirt” out of his eye, reviewing signs with the third base coach, retying a shoe, or whatever. There’s gamesmanship going on both sides that doesn’t really fool anyone and aside from maybe boredom I’m not sure that it really impacts the pitcher/batter match-up all that much.

        I agree with you that in the situation that you described (a pitcher getting shelled unexpectedly) that the defensive has more tools to stall than the offense.

  7. Jeremy Conley

    This article gives a lot of good information, but there seems like a pretty easy way to answer this question that wasn’t looked at. Couldn’t you just look to see the average runs scored per inning over the last 5 years? If scoring hasn’t gone down in the late innings, does it really matter whether relievers are throwing harder?

    • Jason Lawrence

      Thanks for commenting. Yeah, Ken Rosenthal talked about fewer runs being scored in the final 3 innings of games–first sentence of the fourth paragraph above. This article is part of a 10-article series we’re doing on why fewer runs are currently being scored in MLB. I’m not arguing that bullpen specialization or improved relievers are the only reason or the best reason that fewer runs are being scored, simply that they are part of the reason. Fewer runs are being scored across the board so it makes sense that ERA is down for both starters and relievers, that’s right in line with point of the series. I’m just looking specifically at the part that relievers and bullpen usage has played into the decreased offense. I think it’s pretty clear that relievers throwing harder makes a difference in getting batters out. Look at our closer. There are many more articles on the way that will help fill in the picture!

      • Jeremy Conley

        Yes, I’m also a participating writer in the series. I guess my point was that if starters and relievers have both gotten better at about the same rate, that would make it seem like pitching in general has gotten better, not that bullpen specialization or matchups have made relievers better.

        From the title of the article I thought you were examining the impact of special bullpen roles and matchups on offense, rather than just saying that relievers have gotten better like all pitchers. Since starters’ ERA has actually declined more than relievers’, I’d like to see some more evidence that matchups and specialization have actually had an impact.

      • Jason Lawrence

        I hear you. I feel like all of the article but maybe the last few paragraphs is talking specifically about bullpen specialization and match ups. It’s pretty clear that managers have been using it a lot more and that it’s effective. I would say it’s part of the reason that relievers’ ERA has declined. Why the starters’ ERA has declined would be a different story. But you’re right, maybe it’s just that all pitchers are better and nothing else matters. The evidence suggests otherwise, and I included quite a bit of it, but you’re not getting that from the article, which is unfortunate. Let me know if you find anything else or you think of a better way of looking at it and maybe I can post an amendment down the road.
        Looking forward to your article!

      • Jeremy Conley

        To the Rosenthal point, the late innings have always been lower scoring. The question isn’t are fewer runs being scored in the later innings than the earlier innings, it’s about the change in run scoring. Since the series is about the decline in offense, you should ask has scoring declined in the later innings more than it has in the earlier innings to see when in the game most of the decline in offense is happening.

        Just looking at starter and reliever ERA seems to suggest that the decline is happening pretty consistently throughout the game, which would lead me to believe that the matchups and specialization actually aren’t having much of an impact.

  8. Jeremy Conley

    So here’s the thing, since 2000 relievers ERA has gone down a full run, from 4.58 to 3.58. However, in that same time, starters ERA has gone down 1.05 runs, from 4.87 to 3.82.

    So that makes it seems like the decline in runs is pretty equal between starters and relievers, so are you sure that matchups and specialization are really having much of an effect? If they are, wouldn’t you expect to see relievers ERAs dropping faster than starters?

  9. The Next Janish

    Not advocating, just saying, the commissioner could always limit the number of pitchers a team has on the roster. If a manager only had three relievers you’d bet we’d see a lot more scoring. Personally I like it how the game is played and if I had my druthers there’d only be 152 games and no inter-league during the season.

  10. Carl Sayre

    The length of a game is a simple solution MLB can set a 2 hour 45 minute time limit on a nine inning game fine both teams 50 thousand dollars for every 5 minutes it goes over. The commissioners office could assess both fines to one team if they felt like that team was intentionally slowing progress. I would wager games would all be 2 hours 30 minutes at the most.

    • JB WV

      Love your premise, but what about the games that go 12-9? or 4-3 with multiple changes when the game’s on the line? As a fan, it doesn’t matter. George Carlin did a good bit comparing football with baseball. “In FOOTBALL we play on a GRIDIRON. In baseball we play on a field…In football the game goes to SUDDEN DEATH. In baseball we play extra innings. In football we penetrate the end zone for a touchdown. In baseball we go home.” I guess the point being, this should not be a regimented game. The subtleties of baseball make it such a unique, relaxing GAME. There’s 162 games per year, at least. The more, the merrier.

  11. Steve Schoenbaechler

    Throwing harder “can” relate to a higher K-rate. However, I don’t believe that would be anywhere near a 100% correlation. For, the league has literally been littered with hard throwing pitchers now and in the past, and their K-rate isn’t any better than the average.

    Also, one must consider pitchers like Niekro and Dickey. They were some of the softest throwers in the league, but I believe their K-rates were one of the higher ones in the league.

    Overall, I’m not worried about K-rates that much. I’m more worried about “Can you get the guy out?” If anything about a pitcher’s “style”, I’d be more interested in starting someone like Dickey then following them with someone like Chapman. Or, starting someone like Clemens then following him with someone like Niekro. In other words, the ability to bring in different styles of pitchers. That’s one thing I did like about Logan. You could bring in a smaller pitcher like Cueto, then bring in someone taller like Logan. Of course, the player still needs to perform well.

    • Steve Mancuso

      Generally speaking, strikeouts are preferable to other outs because the ball isn’t put into play. A ball that is put into play is a threat to become a hit 26-29% of the time. So if you’re worried about “can you get the guy out” you should be worried about strikeouts and therefore velocity because there is a strong, positive correlation.

      Obviously, setting up 100% as the standard between velocity and strikeouts is phony. It’s not perfect – some hard throwers have lower K% rates than others. There are other factors that go into Ks like what the second and third pitches are. And obviously there are outliers for knuckleball and spitball pitchers. But overall, more velocity means more K’s and also a little bit weaker contact (although this last part is controversial).

      I once heard Cal Ripken say there was nothing to the idea that facing different styles of pitchers posed problems. He said that professional hitters adjust quickly and that it never bothered him. He almost seemed surprised by the question.

      • lwblogger2

        I’m certainly not going to argue with Cal Ripken, one of my favorite players of all time and a really good guy to go along with it. I will say that where it makes a difference is when it comes to arm slots, particularly when a guy has a funky delivery (submarine, pauses, etc…). That’s a bigger adjustment than a hard thrower vs soft tosser for example.