In December 2016 the Brewers and the Red Sox made a pretty interesting trade. In that deal the Brewers sent reliever Tyler Thornburg to Boston. In exchange, the Red Sox sent the Brewers third baseman Travis Shaw. There were some minor league player-to-be-named-later-types shuffled around too, but it was basically Thornburg for Shaw.
The deal made a lot of sense for Boston. They needed bullpen help and wanted to make room for Rafael Devers to play. The accomplished the latter part of that deal, but Thornburg -- despite great success across parts of five seasons for Milwaukee -- did not solve the bullpen problem. He developed arm issues early in his first spring training with the Red Sox and didn’t recover, requiring the dreaded thoracic outlet surgery. He came back in 2018 and pitched poorly. He came back again this season and pitched in 16 games to even worse results.
The Red Sox sought to assign him to the minor leagues but, as Thornburg had no options left, he had the right to refuse the assignment and did so. Thus today’s release. The Sox are on the hook for the remainder of his $1.75 million 2019 salary. Thornburg will try to latch on elsewhere but, for now anyway, he appears to be yet another thoracic outlet syndrome casualty.