Farmer will serve as the Tigers' opening pitcher for Sunday's game against the Twins, Chris McCosky of The Detroit News reports.
The Tigers initially planned to call up Jacob Turner from Triple-A Toledo to fill the opening in their rotation, but manager Ron Gardenhire apparently called an audible on that plan. Though Farmer was developed as a starter and picked up 11 turns through the Detroit rotation in 2017, he's worked exclusively in relief for the big club this season, submitting a 4.33 ERA and 1.57 WHIP in 52 appearances. Considering Farmer hasn't worked more than three innings in any of those relief outings, he'll likely face a strict pitch count Sunday in what amounts to a bullpen game.