Tuesday, July 23, 2024
AnalysisCincinnati RedsMLBNational LeagueNL Central

Investigating Luis Castillo’s Struggles

Luis Castillo has been terrible this season. He has allowed 50 runs in 52.1 innings pitched. In fact, the number of runs he has allowed is greater than the number of batters he has struck out (48). In 2021, 153 pitchers have thrown more than thirty innings. Of those 153, only seven have more RA than SO.


  • Luis Castillo/50/48
  • Dallas Keuchel/34/30
  • Riley Smith/26/21
  • Carlos Martínez/36/31
  • Matt Shoemaker/34/33
  • Randy Dobnak/23/22
  • Chase Anderson/31/29

Castillo’s strikeout minus walk percentage (K-BB%) is less than half of what it was in 2020 (10.0% compared to 22.3%). His pK-pBB% is 14.1, a sizable decline from last season’s 20.1 mark.

Castillo is having his worst season yet, and it’s because he is no longer striking out batters at a high rate.

The frequencies at which he has been throwing different pitch types — fastballs (four-seamers and sinkers), changeups, and sliders — are largely unchanged. The velocity of his fastballs is down about one mph but is pretty close to his career average. Interestingly, his changeup and slider are actually dropping more than they did in 2020 (34.1 to 35.3 inches and 35.8 to 39.6).

In 2021, hitters are batting .340 against Castillo’s four-seam fastball and .529 against his sinker (.300 and .263 in 2020). It doesn’t appear as though he is locating his pitches as precisely as he did in the season prior, especially with the fastballs.

I believe Castillo’s biggest flaw is the huge discrepancy in release point between his fastballs and secondary pitches.

It’s even crazier when one looks at just four-seam fastball versus changeup.

Unsurprisingly, he has one of the biggest differences in the majors between his fastball and offspeed/breaking pitches in 2021. His 0.27 foot difference is the 28th highest out of 158 pitchers that have thrown 200 fastballs and 200 non-fastballs.

One of our former writers, Nick Willis Jr., tweeted an interesting photographic comparison from which one can see Castillo releasing his sinker and changeup at practically the same point in the playoffs last season and at two very different positions earlier this year.

The time hitters have to react to the non-fastball (either changeup or slider) is fairly similar, as the two pitches are close in velocity. This probably helps when it comes to the hitter’s timing.

Last season, only three starting pitchers had a lower predictive earned run average (pERA) lower than Castillo: Jacob deGrom, Kenta Maeda, and Shane Bieber.

While Castillo is certainly dissatisfied with his 2021 performance to this point, he should be relieved that his stuff remains intact. Thus, I have faith that he will put it back together. I think there’s reason to believe he is tipping his pitches and that the solution is to either throw his slider slower to create more separation between it and the changeup or to alter his point of release.

If Castillo doesn’t fix his release point problem, his struggles may unfortunately persist.