The Boston Red Sox sit at 72-59 with a 40-13 record since June 25, the best stretch in baseball over that span. The bullpen has been central to the surge. Boston’s relievers have combined for a 2.66 ERA since the deadline, a number no American League bullpen has matched.
That production has come despite losing two key arms. Garrett Whitlock has been on the injured list since August 10 with elbow inflammation. Justin Slaten joined him shortly after with a similar issue.
The relief depth could have buckled. Instead, someone the Red Sox acquired on August 3 made sure it held.
Miller Has Been Dominant for the Red Sox
Erik Miller came to Boston in the trade that sent Marcelo Mayer to the San Francisco Giants. The initial reaction centered on what the Red Sox gave up. Three weeks later, the conversation has shifted entirely.
Across nine appearances and more than nine innings since the trade, Miller has not allowed a single earned run. He has struck out batters at an elite rate while keeping the ball on the ground and limiting hard contact. The left-hander has been virtually unhittable.
Chad Tracy summed it up simply.
“He’s been as advertised,” Tracy said. “And maybe even better.”
GettyBOSTON, MASSACHUSETTS – AUGUST 19: Erik Miller #67 of the Boston Red Sox pitches against the Arizona Diamondbacks during the seventh inning at Fenway Park on August 19, 2026 in Boston, Massachusetts. (Photo by Maddie Meyer/Getty Images)
What Changed for Miller
The dominance did not begin when Miller arrived in Boston. It started about a month earlier, when he made two decisions that reshaped his approach on the mound.
The first shift happened in early July. Miller took over pitch-calling duties using PitchCom, removing the catcher from the decision-making process entirely. Instead of agreeing to whatever came through from behind the plate, he took ownership of every selection. The conviction behind each pitch rose immediately.
“I think there’s power to pressing that button yourself and taking command,” Miller said.
The second change was his repertoire. Miller recognized that his changeup, once a reliable weapon, had stopped producing results. He dropped it from his game-day arsenal completely and moved away from his four-seam fastball as well, streamlining to just two offerings: sinker and slider. His best pitches, thrown more often.
GettyBOSTON, MASSACHUSETTS – AUGUST 19: Erik Miller #67 of the Boston Red Sox reacts after pitching the seventh inning against the Arizona Diamondbacks at Fenway Park on August 19, 2026 in Boston, Massachusetts. (Photo by Maddie Meyer/Getty Images)
What It Means for the Postseason Push
Miller’s emergence matters beyond the regular season. With Whitlock expected to return as soon as this weekend’s series against the New York Yankees, the Red Sox are positioned to carry one of the strongest bullpens in baseball into October.
Whitlock owns a 2.05 ERA across 45 appearances this season and has been dominant against the Yankees throughout his career, posting a 1.67 ERA in 24 appearances against New York. Adding him back to a group that already includes Miller, Aroldis Chapman, and Tyron Guerrero gives Boston a late-inning combination that can match anyone in the American League.
Slaten’s return timeline remains less certain, but the foundation is already in place. Barring further injuries, the Red Sox bullpen has the depth to be a legitimate weapon in the postseason.
Erik Miller on facing his former team and how the transition to Boston has been since being traded 👀
presented by @WBMasonCo 🤝
Final Word for the Red Sox
A 0.00 ERA. A simplified approach. And a pitcher who took control of his own game, becoming one of the most dominant relievers in baseball.
The Red Sox gave up a top prospect to get him. Right now, it looks like they got exactly what they needed.
Red Sox Get Major Erik Miller Boost After Marcelo Mayer Trade