Luis Castillo has already lost his spot in the Chicago White Sox starting rotation; now his spot on the postseason roster could also be in jeopardy.
On Thursday, the White Sox placed Castillo on the 15-day IL with right shoulder impingement and recalled Tyler Davis in a corresponding move. The move appears to be a clear phantom IL stint, allowing Chicago to add another pitcher without having to send anyone down while Castillo continues to receive his salary.
Regardless of whether Castillo is actually injured, there’s a strong case for keeping him off the postseason roster. When he enters a game, no lead feels completely safe.
During his last outing Tuesday, Castillo entered the ninth inning with the White Sox holding a comfortable 14-7 lead. After retiring the first batter he faced, he allowed back-to-back singles, a walk, and then a grand slam to Vinnie Pasquantino, cutting the lead to three and turning what looked like an easy victory into an uneasy final two outs.
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Castillo eventually recorded those final two outs, but outings like this have become far too common since he put on a White Sox uniform.
The 33-year-old right-hander had plenty of red flags before the White Sox traded for him at the deadline. His strikeout rate, once one of the strengths of his game, had fallen significantly to just 19%. He was also struggling to keep the ball on the ground, with his average exit velocity, barrel rate, and ground-ball rate all ranking in the bottom half of MLB — concerns that were only amplified in a hitter-friendly environment like Rate Field.
But given his pedigree, including three All-Star appearances and a fifth-place finish in the 2023 Cy Young voting, he was viewed as a pitcher who could benefit from a change of scenery.
Even if he didn’t return to his All-Star form, his durability and ability to eat innings looked like a valuable asset for a thin starting rotation and a bullpen that has covered more innings than any team in baseball. Castillo led the MLB in games started in 2021 and 2023 and has thrown 170-plus innings in six of his ten seasons, averaging over 150 innings thrown a season.
Just nine games into his White Sox tenure, neither expectation has come close to materializing.
In his first six starts in the black, silver and white, Castillo made it through the fourth inning just twice and lasted beyond the fifth only once. Even when Will Venable turned to an opener strategy for his start in St. Louis, the results didn’t improve. Castillo surrendered three runs on four hits and three walks while recording just eight outs over 2.2 innings.
While there’s an argument that Castillo’s postseason experience could be valuable, there simply doesn’t appear to be a viable role for him on the White Sox’s playoff roster. His ERA has ballooned to 5.85 on the season, while his .270 expected batting average against ranks in MLB’s 11th percentile.
He can no longer be relied upon as a starter after repeatedly failing to work deep into games and putting the White Sox in early holes. He also hasn’t established himself as a reliable long reliever or a viable option in high-leverage situations.
Castillo owns a 5.57 ERA across 23 starts this season, and his numbers have actually been worse in relief, where he has posted a 7.88 ERA across 16 innings. While that sample is considerably smaller, it does little to suggest he has found a reliable role in Chicago.
As things currently stand, the White Sox’s postseason rotation will likely feature Sean Burke, Davis Martin, Anthony Kay and Erick Fedde, although Chicago could turn to its opener strategy with Fedde.
In the bullpen, Grant Taylor, Bryan Hudson, Sean Newcomb and Hagen Smith will likely handle the highest-leverage situations. Noah Schultz and David Sandlin figure to be the primary bulk-relief options, while Jordan Hicks, Huascar Brazobán and Trevor Richards could fill the middle-inning roles.
Ultimately, it will come down to whether the White Sox trust a rookie in Sandlin who only has 40.1 MLB innings under his belt or choose to go with Castillo’s experience. With only 13 pitching spots available, every roster decision carries added weight and Castillo’s inability to establish himself as a reliable starter or reliever could ultimately leave him on the outside looking in when the White Sox finalize their postseason roster
