Since Mike Leake pitched his last game in a Reds uniform on July 28, the team’s starting rotation has been comprised of five rookies: Anthony DeSclafani (25), Michael Lorenzen (23), Raisel Iglesias (25), Keyvius Sampson (24) and David Holmberg (24). DeSclafani has pitched the entire season, making a team-high 22 starts. Lorenzen was promoted in late April to take Homer Bailey’s spot and has made 16 starts. Iglesias spent time in the minor leagues, the Reds bullpen and on the disabled list. He essentially replaced Jason Marquis and has made 9 starts. Sampson and Holmberg were the guys called up to replace Johnny Cueto and Leake. They’ve each made just two starts.

So how have the young guns performed?

Game-by-game breakdown since July 28.

July 28 is the date Mike Leake pitched his final game for the Reds and seems like as good of an arbitrary starting point as any. That’s also when Nick Carrington urged patience. The rotation has spun two full times since then, plus an extra game for Anthony DeSclafani. That’s 11 starts.

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[Key: Opponent, Date, Innings Pitched, Walks, Strikeouts, Ground Ball Rate, Hard Hit Rate, Fastball Velocity, First-Pitch Strike Percent, Swinging-Strike Percent]

Only twice did the starters go longer than 6 innings, but every game the starter went at least 5. Strikeout numbers were good in relation to innings pitched, but walk rates were spotty. Fastball velocity is better than league average (91.6) for everyone but Holmberg. The first-pitch strike rate is around league average (61.6%). The two new pitchers, Holmberg and Sampson, were the lowest in first-pitch strikes, possibly due to nerves. Michael Lorenzen had the two best games in that metric (more on that later). Swinging-strike rates seem highly variable based on opponent, albeit with a tiny sample. The league average is 9.2%. Again, Lorenzen was best over this short stretch.

Season Performance

Here are the season-long numbers for the starting pitchers with at least 9 starts: DeSclafani, Lorenzen and Iglesias. First, the nuts and bolts of strike-throwing:

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Anthony DeScalafani is having a solid year. He’s right around league-average in fastball velocity, first-pitch strikes and swinging strike rate. His strikeout rate is a bit below league average and his walk rate a bit above. That leads to a below-average K-BB% indicator. His ground ball rate is close to league average. He’s given up more hard hit balls than average, although on August 4, he gave up an incredible rate of 60% hard hit balls against the Cardinals (at the same time, he was striking out 9, walking none and giving up only 2 runs) which inflates his overall percentage.

Michael Lorenzen has an above-average fastball velocity, which is a good starting point. But he has been well below league average when it comes to first pitch strikes. It’s worth noting that he’s done much better on that in the last two games (70.4% and 69.6%). Lorenzen is below average on strike outs, but it’s his walk rate that is a disaster. It produces a K-BB% that is awful. He’s also been a bit of a fly ball pitcher.

Raisel Iglesias has been league average when it comes to fastball velocity and first-pitch strike percentage. His deceptiveness produces a high swinging strike and overall strikeout rate. His walk rate has been league average, producing a K-BB% way above the norm. The one red flag with Iglesias is that he has been an extreme fly ball pitcher so far. We’ll have to see how much the Reds use him the rest of the season. Remember, Iglesias spent last year escaping from Cuba.

Those are the fundamentals. They’ve produced these outcome stats:

Kids4B[Key: ERA measures the number of earned runs given up on average over nine innings. That number is influenced in part by factors beyond the pitcher’s control, such as the quality of his defense. The batting average on balls in play (BABIP) has varied between .295-.300 for the league for a long time. It’s believed pitchers have little control over the balls hit in play, so if their BABIP deviated substantially from the .295-.300 range they have been lucky/unlucky or were helped/hurt by their club’s defense. The same is true with runners left on base (LOB%) which is a sequencing or bullpen issue. A higher-than-average LOB% indicates good luck. Fielding Independent Pitching (FIP) adjusts for those defense and luck factors by isolating what pitchers can control. FIP is referred to as an ERA estimator.

The number of home runs per fly ball also remains relatively constant over time, between 10-11%. If a pitcher has a HR/FB over that number, he’s been unlucky on homers. xFIP is an ERA estimator that normalizes home run rates for a pitcher and shows what his ERA would be with normal luck on homers, balls hit in play, runners left on base and defense. SIERA is a further refinement of xFIP that gives pitchers more credit for ground balls and strikeouts.]

Anthony DeScalfani has been near league average on outcome. He’s been a little lucky on home runs, which is why his xFIP and SIERA are higher than his FIP. Kevin Michell recently dove in depth on DeSclafani’s evolving pitch portfolio.

Michael Lorenzen has the highest ERA of the three pitchers. He’s been lucky when it comes to balls in play and runners left on base, which is why his FIP is so high. But he’s been unlucky when it comes to home runs, so his xFIP and SIERA are lower, but still awful. His problem is giving up too many walks. He also had that terrible start in Colorado (8 earned runs in 2.1 innings), which has a huge impact on his ERA.

The ERA estimators have nothing but good things to say about Raisel Iglesias. His ERA is high, but his strong K% and BB% are highly positive indicators for his future.

You Better You Bet

After searchin’ high and low, the Reds front office has stocked their system, including the minor leagues, with promising pitchers. We’ve seen a few of this year as substitutes for another guy and we’ll likely see more as the year goes along. People try to put ’em down, but the starting rotation has held together since the departures of Cueto and Leake.

Regarding the three pitchers – DeSclafani, Lorenzen and Iglesias – who have more extensive track records this year, the early outlook is favorable. Anthony DeSclafani has performed as a league average pitcher, which is great for a rookie. Raisel Iglesias has outstanding strikeout and walk rates, which means he’s demonstrated the highest upside of the three so far. Michael Lorenzen has great stuff. If he develops confidence that he can throw it over the plate, his numbers should improve accordingly. Keep your eye on Lorenzen’s strikeout and walk rates. They’ll show you what direction he’s headed, for miles and miles.