The Boston Red Sox continued reshaping their pitching inventory this week by dealing hard-throwing left-hander Eduardo Rivera to the St. Louis Cardinals, receiving right-hander Juan Garcia in return.
The transaction, first reported by SoxProspects.com’s Andrew Parker, closes the book on Rivera’s brief and uneven stay with the organization after he was designated for assignment just a day earlier.
Rivera arrived in the Red Sox system as a minor-league free agent in June 2024 after the Athletics selected him in the 11th round three years earlier.
The 6-foot-7 Puerto Rican lefty quickly showed the kind of raw power that gets attention, regularly working in the mid-90s and touching higher with a slider that generated swings and misses.
In 2026, he struck out 30 percent of the hitters he faced across 55⅔ minor-league innings while posting a 2.59 ERA, numbers that made his eventual big-league look feel almost inevitable once injuries thinned Boston’s staff.
He made his major-league debut in late April against the Yankees and later took the ball against the Mets and Orioles, finishing with a 0-1 record and 6.30 ERA over 10 innings.
Control remained the sticking point; he walked 12.7 percent of minor-league batters and six of the 44 major-league hitters he faced. A lumbar strain that landed him on the injured list late in the year only added to the case for moving on.
For a club that already lists Aroldis Chapman, Erik Miller, Jovani Morán and several other left-handed relievers on its offseason 40-man roster, Rivera’s combination of size, velocity and remaining options was no longer enough to justify a protected spot. Boston elected to extract a modest return rather than risk losing him for nothing on waivers.
Garcia is an 18-year-old Mexican right-hander the Cardinals signed as an amateur free agent in January 2025.
He has spent both of his professional seasons in the Dominican Summer League, compiling a 6-6 record and 3.87 ERA over 90⅔ innings. In 2026 he started 11 games, struck out 39 in 43 innings and posted a 4.40 ERA.
The Red Sox are acquiring a long-term developmental piece rather than a near-term contributor.
Garcia is still years from even the upper minors, but the exchange lets Boston clear a roster spot while adding a young arm whose strike-throwing profile has already drawn notice within the Cardinals system.
The deal is small in the grand scheme of Boston’s offseason, yet it fits a familiar pattern.
The Red Sox have shown a willingness to cycle through pitchers with major-league experience when depth charts tighten, and Rivera’s limited track record plus injury history made him an expendable piece.
Whether Garcia eventually becomes anything more than a lottery ticket remains to be seen, but for now the club has turned a designated-for-assignment player into another prospect while keeping its remaining left-handed relief options intact.
