The Boston Red Sox made a surprising decision early in the offseason by designating left-handed pitcher Eduardo Rivera for assignment, clearing a spot on their 40-man roster that now sits at capacity.
At just 23 years old, the towering 6-foot-7, 237-pound southpaw from San Juan, Puerto Rico, had shown enough promise in the minors to make the move unexpected, particularly given the club’s other left-handed relief options already in place.
Rivera arrived in the Red Sox organization in June 2024 after the Athletics selected him in the 11th round of the 2021 draft and later released him.
He quickly established himself as a strikeout artist at multiple levels. In 2025, he punched out 108 batters over 87 innings between High-A and Double-A while posting a 2.48 ERA.
This past seaso,n the pattern continued. Across 55 2/3 minor-league innings he recorded a 30 percent strikeout rate—roughly 71 punchouts—against a 12.7 percent walk rate and a 2.59 ERA.
Even in a brief Double-A stint, he looked dominant, and his Triple-A work at Worcester featured the same ability to miss bats.
His average fastball sits around 95 mph and can touch higher, paired with a promising slider that generates swings and misses.
Those tools translated into a brief major-league look.
Rivera made his debut in April and appeared in four games for Boston, totaling 10 innings with a 6.30 ERA and 10 strikeouts.
The sample was small and mixed; two outings were encouraging while others were not.
He finished the year on the injured list with a lumbar strain, which, combined with his elevated walk totals, appears to have factored into the decision.
Boston already carries several left-handed relievers on the offseason roster, including Aroldis Chapman, Erik Miller, and others, so the club apparently felt comfortable moving on.
The designation does not necessarily end Rivera’s time in the organization. He retains two minor-league options, and if he clears waivers the Red Sox could outright him.
Given his age, size, velocity, and consistent ability to rack up strikeouts in the minors, however, it would be surprising if another club did not claim him or work out a modest trade.
For a pitcher still developing his command, the swing-and-miss stuff that has defined his minor-league career remains the clearest reason opposing teams should take a close look.
