Do Pitch Clocks Reduce Velocity?

With the pitch clock coming to the major leagues in 2023, it’s reasonable to wonder, does that mean that pitchers won’t throw as hard in upcoming seasons?

It seems like a theory with logical underpinnings. Under the new rules, pitchers will have to throw their next pitch within 15 seconds of receiving the previous pitch (with no runners on) and 20 seconds or fewer (with runners on base). Since they previously had effectively unlimited time, the reduced amount of time to rest and recover between pitches under the theory would force pitchers to potentially dial back on their effort level, which would result in reduced velocity.

A similar, but slightly different theory is that even if they attempt to throw at the same effort level, they will simply not throw as hard because of less recovery time. They may be throwing at max effort, but that max effort won’t provide as much velocity.

MLB has effectively run a year-long experiment on exactly that at the MiLB level, since all levels of the full-season minors have been using the pitch clock this year (with the exception of the first few weeks of the season).

There were also concerns that the shorter rest periods may increase the risk of injury for pitchers. MLB says in its injury tracking, the injury rate for pitchers in the minors has actually decreased this year. Baseball America has no way to independently verify that data.

The data from the minor leagues doesn’t necessarily provide evidence that velocities will dip in the majors next year.

According to full season MiLB-wide data obtained by Baseball America, the average four-seam fastball in 2018 was 91.4 mph. It was 91.7 mph in 2019. After the coronavirus pandemic canceled the 2020 season, in 2021, the last year without the current pitch clock rules, the four-seam fastball average velocity jumped to 92.3 mph. This year, with the pitch clock in effect throughout the full-season minors, the average is 92.3.

Over the same stretch, the average MLB four-seam fastball has gone from 93.2 mph in 2018 to 93.4 in 2019, 93.3 mph in 2020, 93.7 in 2021 and 93.9 in 2022. That data was gathered from MLB’s BaseballSavant.com.

It’s possible that without the pitch clock, MiLB velocities would have ticked up slightly this year, just as they have at the MLB level. But there isn’t really any dramatic evidence that the arrival of the pitch clock has significantly slowed the steadily increasing fastball velocities. 

So the pitch clock may reduce the amount of time between pitches in the majors next year, but it’s unlikely to reduce velocity.