Do Cutters Kill Fastball Velocity?

“Typically what we see is the more you throw that cutter, you can become dependent on it and you start to overuse it and typically what happens to guys that overuse the cutter is their fastball velocity drops. That has been consistent over the years.” — Orioles Director of Pitching Development Rick Peterson

Last week, Orioles Vice President Dan Duquette staked out a stance for his team: “First of all, the cut fastball, we don’t like it as a pitch, okay?” Focusing first on his contention that no frontline pitchers have succeeded with the pitch, and then on his opinion that the pitch didn’t lead to good results, and finally on his assertion about the developmental impact the pitch has on young arms, we found last week that his stance was defensible if unevenly defended.

But hidden within what Duquette said, and what Rick Peterson said afterwards, is an idea that should be testable. Both Duquette and Peterson made reference to the fact that young pitchers that use the cutter too often adversely effect their fastball velocity.

Peterson was actually very upfront about the relationship he sees between young cutter usage and velocity drops: “a cutter thrown 40 percent of the time for a young power pitcher can become a crutch, then your velocity drops,” he said in his followup to Duquette’s on-field talk with Steve Melewski.

Let’s see what we can find. Using the filters on our leaderboards, I put together a list of qualified starters that used the cutter more than 20% of the time in any given season since 2002. There are precious few veterans that throw the pitch 40% of the time, and it seems folly to make any assumptions based solely on Andy Sonnanstine, Dan Haren, Roy Halladay, Miguel Batista and Jesse Litsch. Since we have two classification methods on our site, I repeated the filter with the 20% cutter threshold for both BIS and PITCHf/x classifications.

The result was a list of 40 pitchers that became our sample. Pitchers that appeared on the list multiple times included Andy Pettitte, Chad Billingsley, Dan Haren, Doug Davis, John Danks, Jon Lester, Mark Buehrle, Mike Leake and Roy Halladay among others. Jeff Zimmerman was so kind as to run an aging curve on the sample:

Well, it certainly doesn’t look like cutters, as a monolithic group, lead to fastball velocity drop. But there are a few caveats buried beneath what look like damning results.

Not one of these pitchers threw in their age 21 season. And if you scan the names above, you’ll see some late-bloomers on the list. There might be something to the fact, as Peterson says, that “the cutter is a pitch that typically is thrown later on in your career, often after you’ve been in the big leagues several years.” Unfortunately, this isn’t something that’s easily test-able. Our big league stats on this go back to 2002, and minor league PITCHf/x stats are not readily available. It passes the sniff test, but then again, it still doesn’t explain why these pitchers didn’t see the velocity loss Peterson predicts.

There’s another twist that comes if you take a closer look at Peterson’s comments: “What happens is you start to get off to the side of the baseball (with your grip) and then you’re no longer consistently behind the baseball.” There’s a belief in baseball that there are two pitches commonly called the cutter. One, called the ‘grip’ cutter, or the ‘cut fastball’ focuses mostly on grip: you hold the ball like a slider, but you throw it like a fastball. You might point to Mariano Rivera, as Melewski did, for a prototype version of the pitch.

The other, called the ‘load’ cutter, or the ‘baby slider,’ has a release to it that is not unlike a slider. Typically, this pitch comes in slower than a regular fastball and slower than the ‘grip’ cutter. Sometimes it has more depth to it than a ‘grip ‘ cutter. And, since Duquette poo-pooed mention of Rivera’s cutter as a fastball, and Peterson emphasized the fact that pitchers get off to the side of the ball, it’s completely believable that they were talking about the baby slider when they denigrated the cutter.

If we were to cut our cutter pitchers into the two groups, it wouldn’t provide us a robust enough sample to say much. As it is, we were limited to 40 pitchers. But, if we were to set two and a half miles per hour difference between the ‘cutter’ and the fastball as a cutoff between the two ‘cut’ pitches — about halfway between a fastball and the five-plus mph slower that a slider travels — we could get a subset of baby slider pitchers. Adam Wainwright, Andy Pettitte, Barry Zito, Chris Carpenter, Cliff Lee, Cole Hamels, Dan Haren, Esteban Loaiza, Gavin Floyd, James Shields, John Danks, Jon Lester, Jon Niese, Josh Beckett, Josh Tomlin, Kyle Davies, Kyle Kendrick, Mark Buehrle, Miguel Batista, Nick Blackburn, Tim Hudson and Tim Stauffer could be your baby slider list.

Since it’s just over half the list, it’s doubtful that removing them would do anything but decimate the sample. Focusing on them as a mini-sample doesn’t produce much, either. There’s a whiff of the late-bloomer about the group, but Wainwright, Haren and Lester were highly touted prospects that did well from day one.

As for velocity loss, it’s unclear. Zito has lost 3.3 mph off his fastball since 2002. He’s 34 now and ‘should’ have lost three mph over that time frame according to Bill Petti and Jeff Zimmerman’s research. Loaiza lost 6.3 mph off his fastball from ages 30 to 36, when he should have lost 3.8 mph, but his career ended with shoulder issues. It’s fair to ask what the role of injury was. Tim Hudson has lost 2.6 mph off his fastball… since 2002… when he was 27. No other ‘baby slider’ pitcher sticks out in terms of velocity loss.

There’s little evidence of accelerated velocity loss among the veterans that use either form of the cutter. There is still a chance that the pitch isn’t good for the development of a young pitcher — certainly the Orioles are not alone in that opinion — and that the veterans that have turned to the pitch are better prepared, and therefore avoid velocity loss.

But then the question becomes when a prospect is ready for the pitch. The Royals ban it before Double-A. The Orioles seem to want to avoid the pitch until the major leagues. Other teams have similar philosophies. Maybe there’s an age at which a pitcher can turn to the pitch without consequence as a fully-formed adult. Maybe we haven’t seen the pitchers that turned to the cutter too young because they lost too much velocity and never made it to the big leagues.

Or maybe the pitch doesn’t actually lead to velocity loss.