A few days after the Marcus Semien-Brandon Nimmo trade marked the first blockbuster of the 2025-26 off-season, the Boston Red Sox decided it was their turn to make headlines on Tuesday, acquiring veteran starter Sonny Gray from the St. Louis Cardinals.

The deal provides Boston with an improved No. 2 starter behind ace Garrett Crochet for next season, addressing a major flaw that contributed to the club’s early exit in the wild-card round of the 2025 post-season. It’s the first big swing of what could be a busy off-season for chief baseball officer Craig Breslow.

For the Cardinals, meanwhile, trading Gray was to be expected after the 36-year-old hurler hinted that he’d be willing to waive his no-trade clause to help facilitate an off-season deal to a contender — which he ultimately did. Both sides mutually decided it was time to part ways, officially putting in motion the franchise’s rebuild under newly-hired president of baseball operations Chaim Bloom.

So, what’s next for both clubs this winter?

In all likelihood, Gray’s departure is probably just the first domino to fall as part of St. Louis’ roster retool/teardown this off-season. Next up could be All-Star third baseman Nolan Arenado, for whom the front office remains open to trading in hopes of getting out from under the remaining two years and $42 million left on his contract, according to The Athletic. 

The Cardinals are also reportedly fielding trade inquiries on left-handed-hitters Brendan Donovan, who’s under club control through 2027, and Alec Burleson, who’s under club control through ’28. But it’ll likely require a lucrative offer for the organization to part with one or both of them.

Donovan, coming off his first-career All-Star selection and scheduled to earn a projected $5.4 million via arbitration in 2026, per MLB Trade Rumors, could be a potential fallback option at second base for the Toronto Blue Jays if free agent Bo Bichette doesn’t return. With his high on-base, low-strikeout profile, the 28-year-old versatile defender would perfectly match the franchise’s identity on both sides of the ball.

Other notable pieces that could be moved include left-handed reliever JoJo Romero (free agent after next season), outfielder Lars Nootbaar (free agent after ’27) and infielder Alec Burleson (free agent after ’28).

Acquiring Gray could be just the tip of the iceberg for the Red Sox brass.

While speaking to reporters on Tuesday, Breslow admitted he isn’t closing the door on future starting-pitching upgrades this winter, especially if such an addition were to bump Gray into the No. 3 spot in favour of another front-line starter to pair next to Crochet.

However, Breslow also shared that most of the heavy lifting will likely fall on the offensive front moving forward, as the team aims to fortify its lineup with a middle-of-the-order power bat — perhaps with someone like Pete Alonso or Kyle Schwarber, who spent half a season in Boston during the 2021 campaign.

Bringing back Alex Bregman also remains a top priority for the Red Sox this off-season. But if they also land another marquee hitter in free agency, it may require subtracting from their current roster to stay beneath the third luxury-tax threshold of $284 million — avoiding any draft position penalties.

It’s also worth noting that they’ve expressed interest in free agent J.T. Realmuto, the top available catcher on this year’s market, although the 34-year-old backstop is still widely expected to re-sign with the Philadelphia Phillies. Nevertheless, it’ll be an interesting situation to monitor as Boston considers potential upgrades over its current Carlos Narváez-Connor Wong catching duo.