The Red Sox have promoted pitching prospect Eduardo Rivera from Double-A Portland to Triple-A Worcester, according to the club’s MiLB.com transactions log.
Rivera is moving up to the minors’ highest level after making two starts for Portland to open his 2026 season. In those two outings, the 22-year-old left-hander posted a 0.90 ERA with 16 strikeouts to three walks over 10 innings in which opponents batted .167 against him.
Although the sample size is relatively small, it nonetheless illustrates how effective Rivera has been in the early going. Among 42 pitchers who have thrown at least 10 innings in the Eastern League this year, Rivera ranks first in FIP (1.67), second in ERA, strikeout rate (41%), and xFIP (2.35), third in strikeouts per nine innings (14.40) and swinging-strike rate (16.7%), eighth in WHIP (0.90), ninth in batting average against and groundball rate (52.6%), 12th in walks per nine innings (2.70), and 13th in walk rate (7.7%), per FanGraphs.
A former 2021 11th-round draft selection of the Athletics out of high school in Puerto Rico, Rivera joined the Red Sox organization as a minor league free agent shortly after being released by the A’s in May 2024. The San Juan native spent the remainder of that season in the lower levels (Florida Complex League and Low-A Salem) before splitting the 2025 campaign between High-A Greenville and Portland.
Rivera was slated to reach minor league free agency at season’s end but instead re-signed with the Red Sox in October. He then pitched for the Cangrejeros de Santurce in the Puerto Rican Winter League, helping them win their 17th title. That success allowed him to represent the island in the Caribbean Series for a second straight year, as well as in the World Baseball Classic.
Listed at an intimidating 6-foot-7 and 237 pounds, Rivera is currently ranked by MLB Pipeline as Boston’s No. 27 prospect. The hard-throwing southpaw throws from a three-quarters arm slot and operates with a five-pitch mix that consists of a 93-96 mph fastball that tops out at 98 mph, an 87-89 mph cutter, an 83-86 mph slider, an 85-89 mph changeup, and a 78-80 mph curveball.
Rivera, who turns 23 in June, is now just one call away from the big leagues. Though he is viewed as more of a reliever in the long run, he should provide some much-needed depth to a depleted starting rotation in Worcester. To that end, it appears as though he is tentatively scheduled to make his Triple-A debut for the WooSox by following fellow lefty Alec Gamboa out of the bullpen on Thursday afternoon against the Syracuse Mets at Polar Park.
Looking even further ahead, Rivera will be eligible for both minor league free agency and the Rule 5 Draft this winter if he is not added to Boston’s 40-man roster by the November protection deadline. That is something to keep in mind as he navigates Triple-A for the first time.
(Picture of Eduardo Rivera: Kenneth Richmond/Getty Images)
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