Comparing the NL Central Pitching Staffs

Let’s take a statistical look at the five National League Central Division pitching staffs (should it be pitching staves?). The goal is to find out where the Reds stand in relation to the other teams in their division.

There is a perfect correlation here between ERA and Wins. The team with the best ERA (Cardinals) has the most wins down to the team with the worst ERA (Brewers) having the fewest wins. Not surprisingly this correlation extends to Saves. The teams with the most wins also have the most saves. It makes sense that the teams that allow fewer runs are going to win more games, although the number of runs they score is equally important. How many runs you score matters just as much as how many you allow. So while the teams in this division line up perfectly in terms of ERA and wins, that is definitely not always the case.

The number of Blown Saves (BS) is dependent on three factors. 1) the number of save opportunities: the more opportunities you have the more chances you have to blow a save. 2) the quality of the pitchers in the bullpen: better pitchers are less likely to allow the runs needed to blow a save. 3) the size of the leads the team has in the late innings: the bullpen is more likely to blow a one run lead than a three run lead.

Reds fans will not be surprised to see that the Reds have blown twice as many saves as the Cardinals despite having a lot fewer save opportunities. The Reds’ bullpen was atrocious early in the season. The last-place Brewers have blown fewer saves than the first-place Cardinals, but the Brewers have had very few save opportunities to blow.

Here we can see that while the Cardinals have the best ERA in the division, their xFIP is not the best. xFIP is an advanced metric called Expected Fielding Independent Pitching. It measures the components of pitching that are under the sole control of the pitcher, particularly strikeouts and walks. Teams and analysts have known for years that pitchers have very little to no control over balls hit into the field of play, the quality of the defense, the stadium, the weather, the umpire, the quality of the hitters, the strike zone, catcher framing and multiple other factors — all of which affect the number of runs scored in the games. You can’t just look at a pitching staff’s ERA or a pitcher’s ERA and give them all the credit for preventing runs or all the blame for allowing runs. There are many factors affecting ERA that are completely outside the control of the pitcher. So if you look at ERA as the only factor or a major factor that determines the quality of a pitcher you are very likely to come to the wrong conclusion, sometimes by a large margin.

Sometimes there are reasons why a pitcher or a pitching staff can outperform their xFIP. If their team has extraordinarily skillful defensive players, or if their catcher is extremely good at framing pitches, or if their ballpark is extremely pitcher-friendly then perhaps they could continue to post ERAs better than their xFIP. But this is pretty rare and the effect is not all that large, certainly not large enough to account for the nearly full run difference between the Cardinals’ ERA and xFIP.

xFIP gives us a way of isolating the true talent and skill level of the pitcher, stripping away all the factors outside his control to focus solely on his actual performance. xFIP has been statistically proven to predict the future much better than ERA does. If you want to know what the Reds’ ERA will be in the second half of the season, the best way to make that prediction is to use their first half xFIP rather than their first half ERA.

This is good news for the Reds because xFIP shows the Cardinals are unlikely to continue pitching as well as they have. The chart above reveals that the Cardinals are probably going to start allowing more runs per game, meaning they are probably going to start losing more games. The Cardinals’ defense is average at best, probably even worse than that. Their ballpark does suppress offense, especially home runs. Their primary catcher, Yadier Molina, is known as one of the best defenders in the game is likely a good pitch framer. His brother Jose Molina was considered the best pitch framer in baseball until he retired last year. These advantages do help the Cardinals but do not account for such a big disparity between their ERA and xFIP.

The Cardinals have the best ERA in the National League, but their xFIP is 5th. The Pirates are 2nd, the Cubs 3rd, the Brewers 8th and the Reds 12th. So while we can expect the Cardinals to start allowing more runs unfortunately they will still be much better than the Reds.

This chart shows some “Luck Factors” that give us a good indication of whether a team has been affected by random variation. The league average BABIP is .295. This shows that the Cardinals have been neither lucky nor unlucky on balls in play. It shows that their defense has not turned batted balls into outs at a higher than normal rate. The Reds have exhibited a much better BABIP than the Cardinals, but the Reds have a superb defense, so it is no surprise that they turn more balls into outs.

LOB% stands for Left On Base %, or the number of runners who get on base that are left stranded at the end of an inning. League average is about 73%. Here we can see that the Cardinals have been very lucky. An 8.2% difference between the Cardinals’ 81.2% and the 73% league average makes a BIG difference in the number of runs allowed. The Cardinals’ 81.2% strand rate is by far the highest in all of baseball and is also totally unsustainable. The highest strand rate in baseball last year was 77.0%. The Cardinals’ strand rate last year and the year before was 74%. So there is no way they will continue to strand runners at the rate they have so far this year. Pitchers have very little effect on their ability to strand runners over the course of a season. Extremely high strikeout rates can sustain a higher than normal strand rate, but not anywhere near 81%, and the Cardinals don’t have a particularly high strikeout rate anyway.

The Cardinals allow slightly higher ground ball rates than average, which helps them to limit home runs to some small degree. Their ballpark also suppresses home runs. A normal home run per fly ball percentage is 10%. It is possible the Cardinals could continue allowing far fewer home runs than the Reds and the other NL Central teams, but we will probably see the gap narrow a bit as the season rolls on.

The Reds’ great defense helps them take away a lot of base hits from opposing hitters, but Great American Ball Park negates much of that advantage by being an easy place to hit a home run. So even though the defense helps the pitchers tremendously the team is still not able to outperform their xFIP.

These stats are perhaps the most important of all. The best way to predict whether a pitcher will ultimately succeed or fail in the major leagues is to look at his strikeout and walk rates. This is bad news for Reds fans. The Reds’ pitching staff as a group has the lowest strikeout rate in the division AND the highest walk rate. That is a very bad combination. I have mentioned numerous times in previous articles that K-BB% is the most important metric for pitchers. The league average K-BB% is 12.1%. The Reds are far below that as a team despite having some good individual performers in this stat, particularly Aroldis Chapman (27.6%) and Johnny Cueto (19.1%). But some of the Reds’ young starters are absolutely dreadful in these stats. Michael Lorenzen ranks 121st out of 122 starting pitchers who have thrown 60+ innings with his scary 2.3 K-BB%, only Blue Jays rookie Aaron Sanchez is worse. Anthony DeSclafani ranks 108th at only 6.9%. Josh Smith is at -10.3% in his two starts. Leake, Moscot, Hoover, Badenhop and Cingrani are also very poor in this stat.

The Reds are in danger of being left in the dust in terms of pitching if their young starters cannot make drastic improvements in their strikeout and walk rates in quick fashion. DeSclafani and Lorenzen in particular are in store for major ERA spikes because their strikeout and walk rates show they have been extremely lucky to have ERAs in the 3.35 range. Their xFIPs show their future ERAs are going to be in the 4.75-5.00 range if they don’t start whiffing more batters and issuing fewer free passes. You simply can’t survive for long by pitching to contact in a homer-friendly ballpark.

In conclusion, the Cardinals have been pitching over their head and are likely to come back to Earth to some degree. The Pirates and Cubs and Cardinals all have good pitching staffs and are going to continue to pitch better than the Reds, but not to the same degree they have thus far. If the Reds trade away Cueto and Chapman their team K-BB% could be historically bad. The Brewers are a mess and are not likely to mount any sort of threat in the near future.