The Reds have gotten a lot of attention for their bats in the early goings, but their starting pitching deserves some credit as well. Tyler Mahle is boasting a 38.8 percent strikeout rate. Jeff Hoffman and Wade Miley both have ERAs under 3.00. Then there’s Luis Castillo, who is supposed to headline the rotation, but has thus far been the goat.
Through four starts, Luis Castillo has given up 17 runs in 19 1⁄3 innings. The glut of those runs came in a disastrous Opening Day start against the Pirates in which he got tagged for 10 runs and failed to make it through the fourth. He followed that up with seven scoreless innings against the Pirates, but he got hit hard in his next two outings.
After striking out 30.5 percent of batters he faced in 2020, Castillo strikeout rate has fallen to 17.8 percent. If the season ended today, his 4.69 FIP and 4.19 xFIP would be the worst marks of his career. Of course, the season won’t end for another five months, so Castillo still has time to put things together. His inauspicious start, however, has cast doubt on whether he can pitch like he has the past two years.
A 17.8 strikeout rate in four starts would be his worst four-game stretch since July 2018 and 2018 was his worst season in an otherwise stellar career. A low strikeout rate in a small sample isn’t the only similarity that Castillo has with his 2018 self. Castillo’s velocity is also down nearly two mph on all his pitches, and in 2018, it was the same case. It’s easiest to see on his fastballs.
It feels strange to worry about a pitch only averaging 95.7 mph on his four-seamer, but Castillo’s fastballs have never been his best pitches. This year, they’ve been getting hammered. Hitters have an expected wOBA of .358 against the four-seamer and .492 against the sinker.
Castillo must be losing confidence in the hard stuff as he’s been throwing changeups more frequently than ever. The change was his most commonly used pitch in 2019 and 2020, but it was still about even with his sinker and four-seamer. This year, Castillo is throwing the changeup 41.3 percent of the time.
Castillo’s changeup is among one of the best pitches in baseball, but even it has been a little worse in terms of results. Per Baseball Savant, the 32.2 percent whiff rate on Castillo’s change is nearly eight points lower than it was in 2020 and 17.5 points lower than in 2019. Across the board, Castillo’s pitches are generating fewer whiffs, and while velocity is a cause, location is factoring in as well.
In 2019, Castillo found success against lefties by throwing his changeup down and away, but in 2021, it’s creeping toward the center of the plate. Likewise, his fastballs are finding the heart of the plate more often and they’ve been getting hammered as a result.
Of course, it’s too early to say that these trends are going to continue. Castillo’s velocity could return as the season wears on and the weather warms up, and his command could return. The Reds have done well without contributions from Castillo so far, but if they’re to contend, they’re going to need him to pitch like he has in the past two years.
Kenny Kelly is the managing editor of Beyond the Box Score.