Brennan signed a minor league contract with the Braves back in March and has been jettisoned after compiling a calamitous 6.91 ERA, 2.09 WHIP and 33/17 K/BB ratio across 27 1/3 innings (24 appearances) for Triple-A Gwinnett. The 30-year-old righty has made 50 relief appearances in the big leagues since 2019.

Brennan made one relief appearance with the Mariners last year and spent the majority of the season at Triple-A Worcester in the Red Sox' minor-league system, posting a 6.69 ERA, 1.57 WHIP and 37/15 K/BB ratio across 37 2/3 innings. The 30-year-old righty will add to the Braves' organizational relief depth entering the 2022 season.

Brennan worked three scoreless innings of relief for the Red Sox earlier this summer but had mostly been pitching at Triple-A. The 30-year-old right-hander hits the free agent market with a career 4.21 ERA in 50 major league appearances.

Brennan was designated for assignment on Sunday and passed through waivers unclaimed. The 29-year-old right-hander holds a career 4.21 ERA, 1.30 WHIP, and 55/31 K/BB ratio in 57 2/3 major league innings.