Sweet signed a minor-league contract with the Red Sox on Dec. 18.
The 29-year-old right-handed reliever previously saw action in the big leagues during the 2023 season, when he made seven total appearances between the Mariners and Athletics. He pitched exclusively at Triple-A Lehigh Valley in the Phillies organization in 2025, logging a 5.47 ERA, 1.49 WHIP and 50:30 K:BB over 52.2 innings.