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San Francisco Giants infielder Marcelo Mayer seen ahead of an MLB game between the Giants and Detroit Tigers at Oracle Park in San Francisco, Sunday, Aug. 09, 2026. Mayer, 23, was acquired from the Boston Red Sox on Aug. 3.
Santiago Mejia/S.F. Chronicle
BOSTON — Each of Buster Posey’s two years as the San Franc isco Giants’ top baseball executive, he has made a deal with the Red Sox.
The first, of course, was an eye-popper, a jaw-dropper, trading for Rafael Devers, one of the game’s top sluggers, six weeks before the actual trade deadline. This year, Posey waited until the last second to move reliever Erik Miller, but when he did so, it was for an infielder, Marcelo Mayer, ranked Boston’s top prospect three out of the previous four years.
Is there, perhaps, some extra affinity between Red Sox chief baseball officer Craig Breslow and Posey? Their playing careers overlapped, with Posey going 1-for-3 off the lefty reliever. Both retired relatively recently, Breslow after the 2017 season, Posey after 2021.
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“I have a ton of respect for Buster as a player and as an executive,” Breslow said. “We’ve both spent considerable time in a major-league clubhouse and on major-league fields, that brings a level of credibility and respect, though he certainly had the more accomplished career.
“In dealing with him, I’ve found him to be honest and straightforward, so I’ve enjoyed the conversations and the explorations of different concepts and ultimately we were able to line up on a couple of trades that I think both sides believe improve the outlook of our respective organizations.”
Giants general manager Zack Minasian noted there are several connections between the front offices, but when it comes to the two bosses, the similar experiences and mindsets certainly play a role.
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“Some of it is teams matching up, but I do think Buster and Craig are both very to the point, and I think that helps get deals done,” Minasian said. “And then a lot of different lines of communication help but two people, I’m sure, have mutual respect for their careers and are both willing to be aggressive to get things done.”
The Giants hadn’t planned to move Miller, one of the most reliable members of their shaky bullpen and a player with three years of service time remaining.
“I think Erik’s got a chance to be one of the better left-handed relievers in the entire game,” Minasian said. “But just given the situation we were in, to get a player like Marcelo with his upside just felt like we had to do it.”
Miller knew his name had been floated in rumors, but, he said, “like a week ahead of time or so, my agent called me and updated me and said (the Giants) said no, that wasn’t something they were looking at or interested in doing, and I believe that. So obviously I was very surprised initially when it happened, but when I looked up and saw the TV and who they got back, you can start to connect the dots.
“I don’t blame them, it’s probably a smart move for them to make. You generally get on the lower end of value for (set-up) relievers, and you get a guy of that stature? It makes sense.”
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Mayer has yet to play for the Giants; he developed some right foot soreness after working his way back from a stress reaction in his left forearm. He comes with all the accolades as a projected No. 1 draft pick (he wound up going with the fourth pick in 2021) and with a lot of fans remaining in the Boston organization.
“His raw baseball skills are off the charts, it looks like the game just comes easy for him and I love him as a person,” said Boston pitching coach Andrew Bailey, who served the same role in San Francisco on Gabe Kapler’s staff from 2020-23. “He’ll take that opportunity and run with it, I’m excited to see where Marcelo’s career takes him.”
Miller is thriving with the Red Sox, entering Sunday having not allowed an earned run in eight appearances with Boston (and overall, in 22 games since June 19). He’s unfazed by changing leagues and coasts and pitching in tight games for one of the most demanding fanbases in the game.
“He’s a stabilizing lefty with elite stuff,” Bailey said. “He’s really turned a corner in his strike-throwing and he has conviction and confidence in who he is on the mound and a simplicity in his style. He’s done a phenomenal job.”
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Miller is happy to find himself in the pennant race, though he was one of the few Giants players who lived in the city full-time and he plans to keep his apartment in Pacific Heights.
“When you’re pitching in games that matter, it’s just a different feeling,” Miller said. “I haven’t really felt that before; I think it’s what every guy wants.”
