ST. PETERSBURG, Fla. -- The White Sox have longed for controllable starting pitching for weeks now, and have also recently signaled their reticence to mortgage their bright future for short-term interests.
Did they just thread the needle?
They've certainly attempted to. Sox Machine can confirm what was first reported by ESPN's Jeff Passan: the White Sox have acquired right-handed starter Luis Castillo from the Mariners in exchange for reliever Seranthony Domínguez, Double-A catching prospect Boston Smith, and Triple-A outfielder Nolan Jones.
Castillo is controllable; he is signed through 2027 at a $22.75 annual salary, with a $25 million vesting option for 2028 bases on innings pitched, per Cot's Contracts. Per a source, there is only a nominal amount of cash being sent from the White Sox in the deal, for consideration of a potential buyout, but Seattle taking on the rest of the two-year, $20 million contract Domínguez signed this winter is the biggest component of absorbing Castillo's cost.
Despite being signed to become the White Sox closer, Domínguez struggled in the first half to the point of being removed from high-leverage work after blowing his fourth and fifth save opportunities of the season on back-to-back days in late-June. He's still running a 13.9 percent walk rate, but the 31-year-old has quietly allowed just one run in his last 10 appearances and lowered his ERA to 3.99 after his best outing in weeks on Saturday.
But while they are not being called up in response to this move, the White Sox have top pitching prospects Tanner McDougal and Hagen Smith readying in Triple-A to contribute to the bullpen.
With Domínguez having fallen out of the high-leverage mix, a through-line in the Sox return are pieces that have not quite felt central to their near-future core. Smith, 23, was acquired from the Nationals this spring for Curtis Mead, who had been designated for assignment when he didn't crack the opening day roster. Mead has had a breakout season and just fetched promising young left-hander Connelly Early in a trade with the Red Sox. But Smith's meteoric development had eased the sting of watching Mead thrive elsewhere.
Hitting a combined .291/.448/.589 with 22 home runs across three minor league levels in his pro debut, Smith had already rocketed up to Double-A despite a 67.7 percent contract rate that portends future hit tool concerns. Such has been the rapid progression of his offense, that it raised the question of whether the relatively raw stage of his catching development--primarily just due to inexperience, not athleticism--was going to stall his ascension to the majors, or just require a position change.
"Defensively, I still think he’s a better athlete than people give him credit for or really realize," said farm director Paul Janish on Saturday in St. Petersburg. "I still think he’s going to be able to play an average corner outfield at the major league level defensively. The fact that he also is going to be able to catch is just the versatility is hard to match."
That sounds more like an interesting 40/45-grade prospect, than a potential power-hitting everyday catcher. So along with the 28-year-old Jones, who lacked a path to the Sox' left-handed outfield mix but offers depth to a Mariners org that just placed Luke Raley on the injured list, there's an argument to be made that no potential core pieces were purged.
Now it's just the matter of if the 33-year-old Castillo, a three-time All-Star and a dependable mid-rotation starter as recently as last year, is a significant rotation upgrade amid a year of career-worst results. Castillo's current 5.06 ERA is the worst of his career, his 19.4 percent strikeout rate is the first time he's been below 20 percent at any point. While Castillo still throws 95 mph, both his fastballs have taken significant damage this season, the whiff rate on his mid-80s slider has markedly declined, and his changeup is a distant fourth pitch, when it was once one of the most devastating offerings in the game.
Castillo has significant postseason experience with a 2.25 ERA in 28 career playoff innings. He throws from a uniquely low arm angle for an organization that loves such things, has a league reputation for being amenable to coaching suggestion, and White Sox pitching development prides itself on finding changeup solutions for pitchers that have struggled to find them. He had seemed frustrated at times under the piggybacking arrangement the Mariners had put Castillo in at times, and while the Sox have not clarified who will be moving out of their rotation to make room for the right-hander, certainly being the big trade deadline add for a division leader will be a more comfortable chunk of runway.
For what it's worth, Erick Fedde and Noah Schultz both just wrapped up some of their best outings of the year this weekend in Tampa, each throwing five innings of one-run ball against the holder of the best record of the American League. But the 22-year-old Schultz has essentially matched (88) his professional career-high in innings (88 1/3) this season already, which could have necessitated a shift in its own right.
