Starters Who Can’t Keep It Up
The pitch clock is one of the various rule changes implemented this season. Some pitchers were going to be affected more than others, but it was tough to know who exactly before the season started. Some names are starting to come to light with Carlos Carrasco blaming the lack of time between pitches for his velocity drop.
Carlos Carrasco could not record an out in the fifth inning of his season debut. His final line:
4+ IP, 4 H, 5 ER, 4 BB, 4 K, 96 pitches.
Carrasco's average four-seam fastball velocity was 91.1 mph, the lowest of any outing in his career. pic.twitter.com/yEmDTDr6a2
— Anthony DiComo (@AnthonyDiComo) April 3, 2023
With most starters having one start under their belts, I decided to see who gained or lost velocity each time through the batting order compared to last season.
To get the information, I went to Baseball Savant’s search page and found the pitcher’s increase or decrease in average fastball velocity compared to the first or second time through the order. I limited the sample to pitchers who have thrown at least five fastballs the second time through the order this season. For last season they needed to throw the majors and see a lineup a second time. In all, 154 pitchers made the sample and here are the results.
| 2022 | 2023 | Change | |
|---|---|---|---|
| Average | -0.36 | -0.50 | -0.14 |
| Median | -0.3 | -0.6 | -0.3 |
It should not be a surprise that velocity declines, it’s just more, so far, this season. Using a previous study of mine, the additional 0.14 mph drop would equation to a 0.04 increase in ERA and a 0.2% drop in K%. Not a ton on the aggregate, but the drop was more for some pitchers than others. I looked into two factors to see if one group of pitchers where more affected than others.
The first was age. Possibly older pitchers needed more of a break between pitches. The second was the “Tempo” or time between pitches as measured at Baseball Savant. For the Tempo measurements, I used the 2022 times with runners on base and not on base. Here are the results.
| Change | Avg Age | Avg Temp (no runners) | Avg Tempo (runners on base) | Count |
|---|---|---|---|---|
| <= -1.0 mph | 30.2 | 17.6 | 23.3 | 23 |
| 0.1 to 0.9 mph | 29.4 | 17.1 | 23.2 | 70 |
| 0 to 0.9 mph | 29.3 | 17.6 | 23.3 | 48 |
| >= 1 mph | 30.2 | 17.8 | 23.0 | 13 |
There was not a whole lot there but there was more of a decline for those who took a while with runners on base. I dug in a little more. I ended up with three 2022 Tempo groups and their average velocity loss from 2022 to 2023.
| Temp Range | Avg Velo Drop | Count |
|---|---|---|
| >= 23.5 | -0.25 | 73 |
| >22 & < 23.5 | -0.08 | 40 |
| <= 22 | 0.00 | 43 |
There is definitely a threshold where pitchers start to struggle. The deal is that when the thresholds where expanded to all pitchers, last season’s slow Tempo pitcher group included a total of 330 pitchers. It’s not just a dozen or so guys but most of the league.
I don’t have a solid reason why the increased velocity drop only shows up with runners on base, but I have two theories.
- Maybe the “slow” to-home guys don’t have their normal amount of time to hold runners on and feel they need to rush their pitches.
- Maybe they needed more time to recharge from the stretch versus from the windup.
Or it could even be a combo of both. Or something I haven’t thought of. It’s just tough to tell right now.
Besides the overall thresholds, it is important to know who to worry about. Here are the pitchers to freak out about who have see their velocity drop by more than 1 mph when comparing the first and second time through the order for the last two seasons seasons.
| Name | 2022 TTO FBv Change | 2023 TTO FBv Change | Diff |
|---|---|---|---|
| Strahm, Matt | 0.9 | -1.8 | -2.7 |
| Darvish, Yu | -0.2 | -2.4 | -2.2 |
| Davies, Zach | 0.1 | -1.9 | -2 |
| Gray, Josiah | -0.1 | -2.1 | -2 |
| Hunter, Tommy | 0.3 | -1.5 | -1.8 |
| Boyd, Matthew | 0.2 | -1.5 | -1.7 |
| Carrasco, Carlos | -0.3 | -1.8 | -1.5 |
| Lauer, Eric | 0 | -1.5 | -1.5 |
| Morton, Charlie | -1.2 | -2.6 | -1.4 |
| Alcantara, Sandy | 0.2 | -1.1 | -1.3 |
| Weathers, Ryan | 0.1 | -1.2 | -1.3 |
| Flaherty, Jack | -0.3 | -1.6 | -1.3 |
| Wacha, Michael | -0.2 | -1.4 | -1.2 |
| Manoah, Alek | 0.6 | -0.6 | -1.2 |
| Sale, Chris | 0.5 | -0.7 | -1.2 |
| Urías, Julio | 0.6 | -0.6 | -1.2 |
| Wentz, Joey | -1.4 | -2.5 | -1.1 |
| Kopech, Michael | -0.2 | -1.3 | -1.1 |
| Ryan, Joe | -0.6 | -1.7 | -1.1 |
| Kaprielian, James | -0.2 | -1.2 | -1 |
| Oller, Adam | -0.7 | -1.7 | -1 |
| Schmidt, Clarke | -0.5 | -1.5 | -1 |
| Corbin, Patrick | -0.1 | -1.1 | -1 |
There are some high draft picks on the list (e.g. Alcantara, Darvish, and Manoah) but it has only been one or two starts for them so they could build up some endurance. It has just been a week’s worth of games.
There are a ton of factors to keep track of this season and I just brought up another. With it being a long season, finding little edges will start adding up, especially with pitchers on the fringe (e.g. Joey Wentz).
Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won four FSWA Awards including on for his Mining the News series. He's won Tout Wars three times, LABR twice, and got his first NFBC Main Event win in 2021. Follow him on Twitter @jeffwzimmerman.
I haven’t watched him pitch this year but I think Cookie ditched the traditional windup and pitches only from the stretch, which is consistent with one of your theories. It might be tough to find the data but I wonder if you could filter results and see if the pitchers who only pitch from the stretch are more impacted? I know Strasberg gave up the windup a while ago but he’s still hurt, but there must be others.