The Boston Red Sox released relief pitcher Tyler Thornburg on Wednesday a day after he refused a minor league assignment.
Thornburg, 30, had a 7.71 ERA in 16 appearances, spanning 18 2/3 innings, for Boston this season. He struggled in a rehab stint at Triple-A Pawtucket after a hip injury, with a 12.66 ERA in 11 games.
When the rehab assignment ended Monday, Boston needed to put him on the major league roster or have him accept a minor league assignment, which he had the right to refuse due to his service time in the majors. Thornburg is now a free agent, with the Red Sox owing him the balance of his $1.75 million salary for this season.
Boston acquired Thornburg from the Milwaukee Brewers after the 2016 season, when he had a 2.15 ERA and all 13 of his career saves.
The right-hander didn't work out to be the back-end bullpen piece the Red Sox had hoped for when they gave up a package that included third baseman Travis Shaw and recently promoted infielder Mauricio Dubon. Thornburg missed the 2017 season after undergoing surgery for thoracic outlet syndrome in his right shoulder. He was 2-0 with a 5.63 ERA in 25 games last season.