Left-hander Craig Breslow was added to the roster in place of May, who was put on the 60-day disabled list. The rehab process traditionally takes approximately 12 months, which means May could be ready for Opening Day 2018.
The 27-year-old May was bidding to make a return to the starting rotation after moving to the bullpen during the 2015 season. He sustained the injury while pitching against Team USA in an exhibition game on March 8.
May posted a 2-2 record with a 5.27 ERA in 44 relief appearances last season with Minnesota. He owns a 13-17 career mark with a 5.14 ERA in 102 games played (25 starts) -- all with the Twins.
Breslow, 36, went 0-2 with a 4.50 ERA in 15 relief appearances last season with the Boston Red Sox. He owns a 22-29 career mark with eight saves and a 3.35 ERA in 539 games played (two starts) while playing for seven different teams.