The White Sox don't call games from the dugout like some organizations have begun to in recent years. But after their biggest acquisition from last month's trade deadline, Luis Castillo, got touched up for five earned runs in four innings during his White Sox debut in Boston last week, input on his pitch usage is coming from pretty high places in the organization.
"I felt he could have gone to the changeup a little bit more," said general manager Chris Getz. "When he did, it was effective, and maybe fell into a pattern with his fastball a little bit."
For what it's worth, which is probably a great deal, the principals involved sound completely on board.
"I'm good with it," Castillo said via interpreter. "That's the second-best pitch in my repertoire. That's a pitch I trust and now I'm going to start throwing it more. That's going to make my other pitches more effective too, which is good. I'm always open to suggestions."
For each of the last three seasons, Castillo has thrown his changeup less than 15 percent of the time; a distant fourth pitch behind his four-seamer (which he feels is his best pitch), his sinker and a slider that has become his most-used secondary. But as he emerged as a young star right-hander with Cincinnati, Castillo dominated with arguably the best changeup in the sport, racking up miss rates on it north of 40 percent in each of the first four years of his career.
In scouting circles, there simply is no discussion of Castillo without talking about his changeup: the first time they saw it, how dominant it was in the minors, whether it was a true 80-grade pitch, and more recently, what's become of it.
The Mariners are exceptional at developing pitching, as evidenced by how they traded Castillo out of their rotation at the deadline despite otherwise adding to a win-now roster, the ongoing debate on when they will promote one of their multiple elite starting pitching prospects to fill Castillo's slot, and by the fact that Castillo's elite changeup became an afterthought, and he still posted a 3.69 ERA in five seasons in Seattle. That's even including the career-worst 5.06 ERA that Castillo had for this season at the time of the trade.
But the Mariners are also an extremely slider-heavy organization is how they approach pitching, in a way that has ultimately been reflected in what the last five years of Castillo have looked like.
"Obviously Seattle is a really good organization, they develop pitching, but they're definitely slider-heavy," said pitching coach Zach Bove. "Naturally, they push the slider more. So understanding where Luis is at, how to get out hitters, I think the changeup, you're going to definitely see an increased usage."
The act of supinating your wrist to spin a breaking ball, or pronating to turn over a traditional straight changeup are opposite movements, and pitchers often excel at one or the other. From afar, scouts have speculated whether Castillo's greatest skill was in the wrong home in Seattle.
"It can affect the shape of the changeup, obviously some mechanical factors that we have identified," Bove said of Castillo's heavy slider usage. "So all those shapes can have a multitude of effects on the arsenal as well, the delivery as a whole."
However, by far the bigger adjustment to Castillo's usage since he was dealt to the Mariners in the middle of the 2022 season has been an increase to his four-seamer usage. And to their credit, Castillo's four-seamer remains a top-10 bat-misser in the sport among pitchers who have thrown 750 or more this season (27.2 percent, just ahead of Sean Burke). When asked about the source of his changeup's decline, Castillo identified a different inflection point.
"In 2022, I had some shoulder issues," Castillo said via interpreter. "I missed the first month of the season, and then when I came back, my changeup wasn't as good as it used to be, and then I got traded to Seattle. When I got there, my changeup still wasn't as it used to be. Then they helped me with the slider to try to be more effective, because the changeup wasn't there. That was when I started throwing the slider more. But it wasn't because their philosophy about the slider that my changeup wasn't as suitable."
For the better part of four seasons in Seattle, it worked. Castillo finished fifth in American League Cy Young voting in 2022 thanks in part to the Mariners' adjustments, and made two exceptional playoff starts that year. He also made two more last year, which were a mixed bag, but experience is experience, and Castillo believes it offered lessons that he will try to impart on a young White Sox team.
Just like Castillo's dalliance with a piggybacking role that the Mariners wedged him into, which at this point he refers to as a detriment in matter-of-fact fashion, it's an incomplete explanation for why he's enduring the worst results of his career. In both cases, with the Sox entrusting him to absorb innings as the workhorse starter he's always been, and asking him to invest time and energy into restoring his changeup, Castillo feels there's a lot to be said for comfort and confidence.
"I think I can improve it, for sure," Castillo said via interpreter. "I've been throwing it more lately with more intensity and with more confidence. I think you could notice that in my last outing. I threw a few good changeups during that outing. It's a work in progress, but I feel there's room to improve with that pitch."
Ultimately, the White Sox believe they bought low on one of the best and most reliable right-handed starters of the past decade in MLB, who still just 33 years old and sits 95 mph. When you invest in a guy like that, there's sort of an overriding belief that he's going to figure it out, in some way.
"I love the vibe, watching him pitch," said Getz. "Over the long haul, over the remainder of the season, it’s going to be a big boost for us."
