HOUSTON — If there was a theme of Luis Castillo’s previous three starts, other than ineffectiveness, it was struggling to establish his four-seam fastball at the top of the zone.
In outings against the Cubs and Twins, Castillo gave up first-inning homers on fastballs that stayed hittably thigh-high. By the time he found the feel on locating heaters elevated enough to set up the rest of his arsenal, the opportunity for a respectable line score was already gone.
“There’s some delivery stuff that goes along with that,” White Sox pitching coach Zach Bove told the Sun-Times. “But that’s what he needs to do, that’s what sets up the arsenal as far as the slider and changeup working off that.”
In that vein, Astros star Jose Altuve opening up the scoring Thursday against Castillo with a first-inning two-run homer on a helmet-high fastball felt like the Sox right-hander getting punished for doing what he’s supposed to do.
Instead, the bloodletting that followed in a 6-2 defeat to clinch a losing road trip — the fifth time in Castillo’s six starts with the White Sox where he’s allowed four runs or more and lasted fewer than five innings — suggested there are no simple solutions to what’s ailing their prized trade-deadline acquisition.
“I would like to know why,” Castillo said of his struggles via interpreter. “That is something that I’m still trying to figure out.”
At least, not solutions like yanking Castillo out of the rotation after a 7.52 ERA in six starts.
“We believe in him,” manager Will Venable said postgame. “I just had a conversation with him just to reaffirm that.”
Will Venable on Luis Castillo pic.twitter.com/OT54Lzzf5p
— James Fegan (@JRFegan) September 3, 2026
With better luck, Castillo’s worst results to date in a Sox uniform — 4 IP, 6 ER–could have been somewhat better. Isaac Paredes’ RBI double in a four-run Astros’ third is a deep, but routine fly out in most MLB stadiums. Daulton Varsho’s two-run triple was set up by misfired fastballs, but came on a slider well below the zone. Christian Walker’s RBI single to plate Varsho was one of the softest hit balls of the afternoon.
But these are all possible when the 33-year-old Castillo, once a preeminent strikeout artist, is not missing bats. Castillo had a career-low 19.4% strikeout rate when he was acquired on Aug. 2, and has struck out 18.4% of hitters in a Sox uniform. Castillo says he feels good physically, but his velocity was down a tick, to approximately 94 mph, for the second-straight start.
It’s far-fetched that Castillo is done being an effective major league starter. But it also is unlikely that a turnaround from season-long struggles, over three weeks that could dictate the winner of the American League Central, is imminent.
With 22 games left, Venable says he’ll be managing like it’s the playoffs in the final stretch, meaning openers used in front of Castillo and others. But the Sox simultaneously seem content to dance with who they brought, an approach that extends to ideas of sliding a slumping Munetaka Murakami down in the lineup after a 3-for-24, 12-strikeout showing on this road trip.
“There have been at-bats where I’ve been thinking too much about getting the angles too much higher on the swings,” Murakami said via interpreter. “Even on the normal outs, I’ve been a little bit negative on the mental side, about even if I have a good at-bat and it’s an out, I’ve been a bit negative. It’s important for me to think in a positive way.”
Even with their deadline additions not providing a boost, there is stuff for the Sox to be positive about. They remain up three games in the AL Central, they return home this weekend to a soft slate of opponents. They control their playoff destiny to an enviable degree, even if it feels like they’re waiting to play like the team they’ve flashed signs of being.
“One trigger, one little key,” Murakami said via interpreter. “It’s about finding that one little thing and moving on forward so I can get back on track.”