The Difference for Homer Bailey

It’s been long enough that I think it’s easy to forget Homer Bailey was a top prospect. Between 2007-2008, Baseball America ranked him No. 9 overall, between Franklin Morales and David Price. A year earlier, he was fifth overall, between Phil Hughes and Cameron Maybin. Hughes was supposed to blossom into a guy who pitched like an ace. He hasn’t yet. Bailey was supposed to blossom into a guy who pitched like an ace. He has, now, having reached a new level with the Cincinnati Reds. Hitters are the ones who’re supposed to peak at 27, but Bailey stole a page out of their book, and now word is he’s on the verge of inking a long-term contract extension to stay where he is in Ohio. A year away from free agency, the talk is that Bailey’s looking at nine guaranteed figures.

Bailey was already a pretty good starting pitcher, before leveling up. He never let anything get out of control, and for a few years he was in the vicinity of league-average. But last season, he dropped his FIP- into the 80s, and he did the same with his xFIP-. Because the Reds aren’t a huge-budget ballclub, it’s a risk for them to attempt this kind of commitment, so they’re rolling the dice as an organization on Bailey being more like his 2013 self going forward. Naturally, then, one gets curious about what changed between seasons. Was there any kind of key to Bailey’s improvement?

His walks hardly budged. His groundball rate hardly budged. In 2012, Bailey struck out 168 batters. In 2013, he struck out 199 batters, despite 25 fewer plate appearances. You don’t have to look further than that — that’s the key, right there. But we can dig deeper.

Bailey didn’t change much about his pitch mix. He didn’t change much about his pitch movement, or his pitch release points. There was, however, a change in his pitch velocities. His fastball gained an average of 1.6 ticks. His slider was up 0.9. His curve was up 1.5. One of the things we’ve learned in recent years is that pitch velocity tends to start gradually declining upon a guy’s promotion to the majors. Bailey had a significant increase, after already having been an established big-league starter.

Again, that would be another potential stopping point. Bailey’s strikeouts went up, and his velocity went up. That’s the story. But we can dig deeper still. Overall he pitched in a pretty similar way, but he dropped his contact rate a little bit, both in the zone and out of it. Sometimes pitching coaches say that they don’t care about velocity. They’re lying, or they’re stupid. Having more velocity lets a pitcher get away with more things.

Here’s where things get particularly interesting. I’m going to show you some splits. First, Bailey’s xFIP against left-handed hitters. Then, his xFIP against right-handed hitters. I know it’s kind of weird to split xFIP by handedness, but it does a good job of distilling the profile into a single telling number.

Bailey vs. LHB

• 2010: 3.50 xFIP
• 2011: 3.44
• 2012: 3.76
• 2013: 3.61

Bailey vs. RHB

• 2010: 3.89 xFIP
• 2011: 4.03
• 2012: 4.09
• 2013: 3.10

Against lefties, Bailey didn’t really change at all. His whiff rate stayed about the same, and the other rates stayed about the same. Against righties, Bailey was like a different pitcher. Not only did he keep half the balls in play on the ground — he lifted his strikeout rate from just over 17% to just under 25%. Last season, Homer Bailey improved, and his improvement was almost entirely contained in showdowns against right-handed hitters.

Two years ago, facing Bailey, righties made contact just over 78% of the time. Last year, they made contact just under 73% of the time. His split strikeout rate improved by 7.4 percentage points, which was the seventh-biggest increase in baseball between 2012-2013 among pitchers to collect significant playing time. Only 11 pitchers improved against righties by at least five percentage points. For Bailey, you could make the argument this improvement was overdue.

See, before last season, Bailey was one of the rare pitchers in baseball with a reverse platoon split. He had a 4.26 FIP against righties, and a 4.19 FIP against lefties. He allowed a .329 wOBA to righties, and a .328 wOBA to lefties. Last season, Bailey shut righties down, and in so doing pitched more like a normal righty with normal behavior. Some might refer to that as simple regression, but it appears like meaningful improvement.

Given the velocity uptick, it’s strange to observe a big jump against righties and no jump at all against lefties. This is where I point out that pitching is complicated. But righties might’ve already had a briefer look at the ball, and perhaps they observed a bigger uptick in perceived velocity. The result was that all of Bailey’s pitches were weapons. He had more success avoiding contact up in the zone. With two strikes, he significantly improved his strikeout rate with his fastball, his slider, and his curveball, and he also threw a few extra splitters. I’m very much aware that pinning this on velocity is labeling correlation as causation, but I do feel pretty good about that, pending other explanations.

Let’s say that a huge part of Bailey’s performance improvement was velocity improvement. Then it’s important to try to figure out where the velocity improvement came from. It might be as simple as health. Bailey threw a similar fastball in 2009. In 2010, he went on the disabled list with shoulder inflammation. In 2011, he was on the DL out of camp with a shoulder impingement, and later he was back on the DL with a shoulder sprain. It could just be that Bailey took until 2013 to return to 100%. It could also be that Bailey made a few minor mechanical tweaks that allowed him to convert more energy into velocity, or however it is the experts put it.

Between 2002-2013, I identified 62 starting pitchers who threw at least 50 innings four years in a row, and whose average fastball velocity increased at least one mile per hour between year 2 and year 3. Out of that group, 42 of the pitchers saw their velocities increase right after seeing their velocities decline. Of the remaining 20 pitchers, 17 saw their velocities decrease between year 3 and year 4. They averaged 89.8 miles per hour before the improvement, 91.3 miles per hour after the improvement, and 90.5 miles per hour the year after that. What’s suggested is that Bailey might be in line to give some of his velocity improvement back.

But for one thing, he can afford to give back some of it. And for another thing, what’s true for a group isn’t always necessarily true for the individual, and it all depends on where Bailey’s extra velocity really came from. If the Reds believe that it’s sustainable, and if it is sustainable, then Bailey might well be his new self, for some time. The most recent version of Homer Bailey was a complete version of the top prospect he was just a few years before.