White Sox acquire veteran pitcher Luis Castillo in deal with Mariners

LaMond Pope, Chicago Tribune on Aug 2, 2026

Published in Baseball

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ST. PETERSBURG, Fla. — The Chicago White Sox will look to lean on Luis Castillo’s vast experience after acquiring the right-hander Saturday night in a trade with the Seattle Mariners.

“His reputation within the league is excellent,” Sox general manager Chris Getz said during a videoconference call on Sunday. “The leadership qualities, the type of teammate that he is, the work ethic. Someone that is not going to be scared, is a fearless competitor.

“The amount of people that I talked to regarding what he brings to the table in terms of being the competitor and the person, it was about as glowing as I’ve heard about any player. And then you put that into the impact that it can have on just the entirety of this team, this pitching staff, it just became more and more attractive. And really happy that we were able to get this deal done.”

The Sox sent reliever Seranthony Domínguez along with minor-league outfielder Nolan Jones and catcher Boston Smith and conditional cash considerations to Seattle to complete the deal.

“Really excited about Castillo, a guy who’s had a lot of success in this league for a long time,” Sox manager Will Venable said.

Castillo, 33, is 3-9 with a 5.06 ERA in 20 outings (17 starts) this season. He has 86 strikeouts and 32 walks in 99 2/3 innings.

He is 87-93 with a 3.65 ERA in 263 career outings (260 starts) over 10 seasons with the Cincinnati Reds (2017-22) and Mariners (2022-26). Castillo has 1,579 strikeouts in 1,510 1/3 career innings.

Castillo earned All-Star honors in 2019, 2022 and 2023. He finished fifth in the American League Cy Young Award voting in 2023.

Castillo has playoff experience, posting a 2.25 ERA in six career postseason games (five starts).

“I know that they’ve been playing pretty good baseball here lately,” Castillo told reporters covering the Mariners through an interpreter. “I’m going to come in, be the new guy. And kind of when you’re the new guy, you’ve got to start from zero. Getting to know all the personnel, getting to know everybody.

“Just got to stick to my routine and just keep doing what I’ve been doing here.”

“This was an opportunity to bring in a starting pitcher that we’re really excited about,” Getz said. “Someone that can help lead this young pitching staff. Not only cover innings, but has experienced pitching in the playoffs.”

As of Sunday afternoon, the Sox were still working through the plan of when Castillo would make his debut. With his addition to the rotation, the Sox will shift Erick Fedde into a bullpen role.

“Luckily I have those experiences in my career,” Fedde said. “It’s one of those things you’ve got to be a little more focused on prep and make sure you keep yourself in a good position. They are keeping me stretched out, so it’s not going to be something like where I’m throwing three days around. It shouldn’t hopefully be too bad.”

The Sox traded away a bullpen arm in Domínguez. The right-hander went 4-3 with a 3.99 ERA and 12 saves in 43 outings for the Sox. He signed a two-year deal with the team in the offseason and spent a portion of the season as the closer. Domínguez went through a rough patch but has been better of late.

“Made an incredible impact on the field, and in the clubhouse,” Venable said. “Just really appreciated everything that Seranthony did for us.”

The Sox acquired Jones in a trade with the Cleveland Guardians in June. He hit .227 with six home runs and 28 RBIs for Triple-A Charlotte after the deal. Jones has a .247 average with 30 home runs and 137 RBIs in 349 major-league games over four seasons with Cleveland (2022, 2025) and the Colorado Rockies (2023-24).

The Sox acquired Smith in a March trade that sent infielder Curtis Mead to the Washington Nationals. Smith, 23, had a .291 average with 22 home runs and 58 RBIs in 78 games between Single-A Kannapolis, High-A Winston-Salem and Double-A Birmingham.

“Unfortunately when you make these moves, it’s going to get a little uncomfortable with the player that you’re sending when you feel like you’re bringing in talent our way,” Getz said. “You’re going to have to give up talent going the other way. Boston’s done a really nice job. You look at how we acquired him, when we acquired him and how that has played out, I’m really proud that we ID’d Boston Smith because he turned into an attractive player.”

The Sox and Mariners found the right equation to make the trade.

“Working with (Mariners’ president of baseball operations) Jerry DiPoto is always fun because he’s always willing to engage and I would say in terms of just dialogue and conversations, I just really enjoy talking to him,” Getz said. “And so it’s been going on for the last couple of days. Others in our organization have been in contact with Mariners people as well.

“We were playing around with different concepts and there was a Luis Castillo market and it finally got to the point where it made sense for us to make the match that we did.”

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