Farmer was optioned to Triple-A Toledo after Friday's game, Anthony Fenech of the Detroit Free Press reports.
He tossed two perfect innings of relief in Friday's game, striking out three, so he leaves on a high note. Farmer will be stretched out in Triple-A as a starter, but could return to the big leagues in either capacity, depending on what the Tigers need. Alex Wilson will be activated from the disabled list Saturday as a corresponding move.