When a Limited Repertoire’s a Good-Enough Repertoire

I was reading something about Clayton Kershaw the other day. Kershaw’s been the guy to write and read about, because he’s been amazing, and because he just got paid, and because there sure as shoot hasn’t been anything else happening around the league. This is the article, and it talks about Kershaw’s ongoing search for a reliable changeup, to go along with all of his other weapons. A particular section:

And so I am boundlessly curious about the changeup, the mystical less-is-more pitch, and Kershaw’s curiosity for it, and the evolution of Kershaw as a pitcher and if there is room for another pitch along the way.

Pitchers like to say the hitters will decide. So far, hitters aren’t suggesting Kershaw needs another pitch. One or two fewer, maybe.

Read it over quickly and you might dismiss that as a worthless old bromide. But there’s a lot of truth tucked away in there — hitters will let pitchers know when they need to make changes. If a pitcher isn’t having problems, the pitcher’s having success, and success isn’t something you mess with unless it gets threatened. Kershaw’s facing no threat, but then this isn’t about him.

There are young starting pitchers in baseball right now. A whole mess of ’em. One of them goes by the name of Michael Wacha. This is about him, and some others. Shelby Miller. Tony Cingrani. Sonny Gray. Chris Archer. A certain pitcher-type in general. From those five specific starters, the worst major-league ERA- last year was 85. The worst xFIP- last year was 100. It’s probably time to say something about limited repertoires.

People ask about these guys in chats all the time. Wacha and Cingrani especially, it seems like. And they ask for a particular reason. According to conventional wisdom, in order to be an effective starting pitcher in the major leagues, it’s all but mandatory to have three pitches. Three reliable pitches, that is, and if you’ve got a fourth one, all the better. Wacha’s got two reliable pitches. Miller’s got two reliable pitches. Cingrani might just have one, to be honest. Gray lives off his fastball and his curve. Archer lives off his fastball and his slider. So, fans are concerned, and curious — what does the future hold for these guys? How important would it be, really, for them to fill out their respective arsenals?

The conventional wisdom makes some sense, absolutely. Relievers usually have two pitches. Having a third pitch allows the starting pitcher to give the hitters different looks, from both sides of the plate, in any inning. Over a long outing you have to avoid being predictable, and so forth. But we might as well do what we can with the numbers we have, to see how they shake out. And it just so happens we have pitch-type data ranging all the way back a dozen years.

So I collected that data for all starting pitchers over the past dozen years, season by season. I made note of their ages, and I eliminated knuckleballers, since they’re complete and utter freaks. At that point, I settled on a 10% frequency cutoff. That is, I considered a pitch type reliable if the pitcher in question threw it at least 10% of the time. It’s somewhat arbitrary, but it feels good enough to me to work. For each pitcher I calculated the number of reliable pitches, and then I grouped all the player-seasons by age. How do the one- and two-pitch starters come out looking?

• Through 25: 26% of WAR in 27% of the innings
• Ages 26-30: 26% of WAR in 25% of the innings
• Ages 31-35: 23% of WAR in 22% of the innings
• 36 and up: 44% of WAR in 37% of the innings

Things get kind of weird in the 30s, perhaps owing to smaller sample sizes. If you just combine the last two into a group of starters 31 and older, then one- and two-pitch starters account for 30% of WAR in 26% of the innings. Those limited starters who remain are still able to have success, and if it becomes more important to have a broader repertoire over time, as you lose velocity, that doesn’t show up here. It seems like the limited starters do just fine, relative to the rest of the starters.

There’s a considerable history of two-pitch starters making it and lasting a while, despite the on-paper disadvantage. Ervin Santana, right now, is an upper-tier free agent. Randy Johnson did almost everything with his fastball and slider, although I’ll grant that Johnson was a freak of his own. Tom Glavine loved his changeup and never really developed a reliable breaking ball. Ben Sheets had a fastball and a curve and basically nothing else. David Wells was similar. Jason Schmidt preferred to pair a changeup with his fastball. Brandon Webb leaned heavily on his sinker and curve. Bartolo Colon makes headlines when he doesn’t throw some sort of fastball. Rich Harden wound up a fastball/changeup guy. It goes on, and while these guys aren’t the norm, they’re common enough to have established a precedent. Baseball’s had a lot of successful two-pitch starters. It’s even had successful more or less one-pitch starters.

The gist being: you can make it with a limited repertoire. It just has to be a good limited repertoire. The fewer pitches a guy throws, the smaller might be his margin of error, but as noted before, hitters will send signals when the pitcher’s in trouble, and if a pitcher isn’t in trouble, he’s doing well enough. Which isn’t to say pitchers can’t try to improve, and it probably couldn’t hurt to have an expanded repertoire, but if opposing batters struggle to do damage, that’s the most meaningful thing. At the end of the day, pitchers are just trying to get outs, and they don’t get bonus points for getting outs with the broadest pitch variety.

Everything being equal, it’s presumably better to have more pitches. But it’s important to keep in mind that when we’re looking at the major leagues like this, everything isn’t equal. The starters who make it up with fewer pitches are selected for being in possession of particularly good pitches, pitches that allowed them to have success at every lower level. They would’ve had to prove themselves as starters, and odds are, each pitch has a higher average quality rating than each pitch belonging to a guy with a greater number of pitches. Wacha, for example, was selected because the Cardinals believed he could succeed out of the rotation, despite really just having a fastball and change. And then Wacha, sure enough, had good initial success. If a guy’s in the majors and starting with two reliable pitches, that right there tells you that he probably has quality stuff.

It’s different, probably, for prospect evaluation. At the lower levels, it might be more important to try to fill out repertoires, because that should only help against stiffer competition. But if a guy’s proven himself, he’s proven himself, no matter how he’s gone about doing it. By the time a guy’s in the majors, he’s passed some really hard tests. By the time a guy’s had early success in the majors, he’s only passed more.

Take a guy like Tony Cingrani. Cingrani would probably benefit from having a better change, or from having a more reliable breaking ball. Cingrani could absolutely improve — as a starter last year, he had an average FIP, and he didn’t work very deep. But then, literally everyone could improve, and Cingrani also struck out 28% of batters. He shredded his way through the minors. He’s already effective, and there’s little reason to believe hitters will suddenly be able to pound him after they adjust. Those adjustment periods are probably overstated.

There’s nothing more important for a pitcher than being able to get big-league hitters out. That is, there’s nothing more important than results. The process is important in its own right, but it shouldn’t be over-weighted. Worry about pitchers when there’s reason to worry. Don’t try too hard to anticipate those reasons. We’re not very good at it.