Trying to Improve Corey Kluber

I wouldn’t recommend watching a large percentage of the little spring-training videos they make available at MLB.com, but this is a fun one. Members of the Indians rotation are asked which individual pitch they’d like to borrow from one of their peers. The responses, arranged in my own preferred order for editorial purposes:

• Josh Tomlin: Carlos Carrasco’s changeup
• Corey Kluber: Danny Salazar’s changeup
• Carlos Carrasco: Corey Kluber’s curveball
• Cody Anderson: Corey Kluber’s curveball
• Danny Salazar: Corey Kluber’s slider, by which he means curveball

It’s a gifted rotation, blessed with a number of elite individual weapons, but you see all the support for Kluber’s hook. By how fast it goes, and by the way that it moves, it’s a pitch unlike almost any other, and it’s been a huge part of Kluber’s emergence. That’s easy to see in the numbers we have. What’s easy to see, as well, is that Kluber throws a cutter that’s been roughly as valuable as the curve. Kluber actually has two elite pitches. What if he pitched like it?

This is when I should stop and remind you that Corey Kluber, as is, is fantastic. Kluber is already one of the best in the game, and there’s nothing for the Indians to complain about. He’s struck out 28% of his opponents, and he’s run low ERAs despite months upon months of sloppy defense. Everything after this is half-suggestion and half-thought experiment. This is as much for me as it is for Kluber.

Kluber is one of those off-the-radar breakthrough guys, and when a player like that takes the spotlight, they get asked on a daily basis what they did to get better. Kluber’s been through all that, and without fail, he’s identified his two-seamer. One day, when he was struggling in the minors, he started throwing a two-seamer instead of just relying on his four-seamer, and then things started to click. With the sinker, everything fell in place, and Kluber liked the feel of the running fastball in his hand. He liked how he could spot it, and he liked how he could keep it down.

Kluber sees the two-seamer as central to his success, and it’s not like there’s any reason to doubt him. He’s right when he says that other pitches work off of the fastball. He says his more spinny pitches were less effective before hitters had to respect the heat. Given all that, let’s look at a little information. Kluber stepped forward in the majors in 2013. Since then, 122 starters have thrown at least 300 innings. Here’s a table of run-value rankings, with pitches put over a common denominator.

Since becoming a quality big-leaguer, Kluber’s fastball has been hit around. It had a negative run value in 2013, it had a negative run value in 2014, and it had a negative run value in 2015. Kluber has also thrown a half-decent, if occasional, changeup. He knows it’s not real consistent. But what’s also revealed here is that Kluber has thrown one of the very best cutters, and he’s thrown one of the very best curveballs. That’s held true each season, and we shouldn’t expect it to stop.

So we have one negative primary pitch, and we have two strongly positive secondary pitches. Our run-value measurements are far from perfect, since context matters and since all pitches are connected, but what’s implied here is that Kluber might improve if he were to throw his fastball less. It’s not like he needs to eliminate it — that wouldn’t make any sense — but at least based on his own results, Kluber might consider something more like an even balance.

Kluber, each season, has thrown a little more than 50% fastballs. That’s not a very high figure, but then consider a few comparisons. Adam Wainwright has two elite pitches in his cutter and curve, and he’s thrown his fastball about 40% of the time. Felix Hernandez has dropped his fastball usage closer to 40%, as it’s become increasingly vulnerable. Masahiro Tanaka has thrown just 36% fastballs since arriving, armed with the knowledge that his other pitches are better. And Yu Darvish has a career fastball rate of 46%, as he prefers other means of getting hitters out.

Kluber, at least in theory, could benefit from throwing more cutters and curves, and fewer fastballs. The fastball could still remain the primary pitch, but maybe the cutter would become a co-primary weapon. And the curve would show up in greater amounts, particularly in lesser-expected situations. When a pitcher increases his usage of a pitch or two, you expect for those pitches to perform a little worse, since the hitters are better prepared, but then this would be offset by Kluber’s fastball performing better. Hitters wouldn’t look for it so much, and so it would be more effective. Kluber wouldn’t have so many two-seamers getting hit back to the outfield.

As noted, this is theoretical. Maybe Kluber thinks throwing fewer fastballs would leave him more likely to get hurt. Maybe he wants shorter plate appearances, even if a few more of them result in hits. I’m not going to tell Corey Kluber how to do his job, because he’d probably be better than me at both of our jobs, and I recognize that. I’m just a FanGraphs stat dork, but my stat dorkiness is telling me that Kluber might be able to make an easy adjustment, and avoid some more baserunners. Kluber doesn’t need to get better, but that doesn’t mean that he can’t.