Sox not done adding, get coveted bullpen arm in exchange for Mayer

After landing Adley Rutschman earlier in the day, Craig Breslow doubled down by adding another impact piece, making it clear the Red Sox are no longer waiting for the future — they’re chasing a championship now.

Erik Miller, 28, LHP

After acquiring Adley Rutschman earlier in the day, the Red Sox weren't done adding to their roster. Boston shipped former top prospect Marcello Mayer to the San Francisco Giants in exchange for left-handed reliever Erik Miller.

Miller, 28, was one of the most sought-after relief pitchers on the trade market, but ultimately becomes a member of the Red Sox in exchange for the once-promising young infielder.

The 6-foot-5 left-hander has posted a 2.76 ERA with 45 strikeouts over 32 2/3 innings this season. Miller features a power fastball that tops out around 99 mph, a wipeout slider, a sinker that averages around 97 mph, and mixes in the occasional changeup.

Adding Miller further strengthens a Boston bullpen that already owns the best ERA in Major League Baseball. He is expected to slot into high-leverage situations, giving interim manager Chad Tracy another dominant late-inning option and allowing the Red Sox to shorten games with a bullpen featuring Tyron Guerrero, Erik Miller, Garrett Whitlock, and Aroldis Chapman.

The Red Sox are the hottest team in baseball and got undeniably better at the trade deadline. The additions of All-Star catcher Adley Rutschman, Erik Miller, and utility man Eli White aren’t what many speculated Boston would do, but Craig Breslow has a plan. This is a definitive announcement to the rest of the league that the 2026 Boston Red Sox believe they can win the World Series.