The White Sox made a bold swing before the trade deadline, sending prospect Boston Smith to Seattle as part of the package that brought Luis Castillo to Chicago. At the time, it looked like the kind of aggressive move a club makes when it thinks it can steal value from a pitcher who had been struggling. But with Castillo still searching for answers and Smith tearing through Mariners minor league pitching, the deal is starting to look a lot less tidy for the White Sox.
Chicago sent Nolan Jones, Seranthony Dominguez, and Smith to the Mariners for Castillo, who was already carrying a $22.75 million salary next season. That price tag made the move stand out even before the results did. Castillo had posted a 5.06 ERA before the trade, and the White Sox still went after him despite the rough year.
The early returns in Chicago have not helped the case. Castillo’s first start for the White Sox lasted just four innings against the red-hot Boston Red Sox. He gave up five runs on six hits and a walk, and Chicago lost that game on the way to a Boston sweep.
Smith, meanwhile, has gone from a promising bat to a full-blown problem for the team that traded him away. The Washington Nationals drafted him in the sixth round of the 2025 MLB Draft out of Wright State University, though he did not play in the minors until 2026. He was later dealt to the White Sox for infielder Curtis Mead, and once he got into Chicago’s system, he started punishing baseballs.
In 79 games across Low-A, High-A, and Double-A, Smith hit 22 home runs and showed off the kind of plate discipline, power, and athleticism that made him stand out right away. He was especially loud in Birmingham, where he hit .306/.485/.667 with eight home runs in 23 Double-A games.
Now with Seattle, he has somehow taken another step. In six games with the Mariners organization, Smith has hit .381/.458/.1.095, with five home runs in his last five games. Across 21 at-bats, he has nine RBIs and three walks.
Boston Smith's massive week continues, now with his five homers in five games, including two today!@Mariners | @ARTravs | @MsPlayerDev pic.twitter.com/HwvLKcmaSe
That kind of production has made it easy to see why people are so drawn to his bat. Power is the headline, but it is not the whole story.
Smith has a swing that jumps off the page, and for a player in his first year in the majors, the confidence has been obvious. His career minor league OPS now sits at 1.076.
He is still a long way from being an everyday big leaguer, but this kind of start makes it easy to picture him getting there. MLB Pipeline currently ranks Smith as the Mariners’ No. 14 prospect.
The White Sox had reason to feel good about their future behind the plate entering the year, with Kyle Teel and Edgar Quero in the mix. Instead, Teel has struggled badly to stay healthy, and Quero has taken a significant step back offensively. That only makes giving up a bat like Smith’s feel more painful.
The rest of the deal has not done much to soften that blow. Jones has gone 4-for-20 with Seattle’s Triple-A affiliate, posting a .200/.368/.333 line with one RBI.
Dominguez had a brutal first outing for the Mariners on August 4, when he allowed four runs while recording just one out, including two home runs, four hits, and two walks. He has been better in his next 1.2 innings, giving up just two hits and a walk.
The trade may not end up mattering much in the larger picture as the White Sox move out of their rebuild, but Smith’s rise is hard to ignore. He has the tools, the athleticism, and now the kind of early run that makes him look like he could become a major piece for Seattle.
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