Plouffe (oblique) was placed on the 15-day DL on Saturday, Rhett Bollinger of MLB.com reports.
The Twins went ahead and deactivated Plouffe prior to Saturday's game, which may be a sign that he will indeed miss the rest of the season after suffering a strained oblique and strained intercostal muscles Tuesday. Reports from earlier in the week suggested Plouffe was "doubtful" to play again this season, but the team has yet to formally rule out a return.