The left-handed reliever was optioned to Class AAA Rochester after Thursday's first game, in which he faced four batters and allowed two runs. Boshers' spot in the bullpen will be inherited by lefthander Nik Turley, who started three games for the Twins earlier this season.
Righthanded hitters were batting .319 against Boshers this season, and the Indians capitalized by scoring five runs in Boshers' two appearances in the series, totaling three outs. With seven games scheduled over five days, the Twins chose to add a fresh arm, and Boshers' roster spot was the one they chose. Boshers has a 5.16 ERA in 27 appearances this season.
Turley, who posted a 16.39 ERA in three June starts, is at Target Field, and will be in uniform for the day's second game. Aaron Slegers, added to the roster as the designated 26th man as allowed during doubleheaders, will make his major league debut as the Twins' starter.