Cousins landed on the 10-day injured list with a strained right biceps Saturday.
With just nine days left on the schedule, the move ends Cousins' regular season. Whether he has a chance to return during the playoffs is unknown. He'll finish his rookie season with a 2.70 ERA in 30 innings of relief, with his 35.2 percent strikeout rate proving to be more than enough to overcome a 15.2 percent walk rate. Miguel Sanchez was recalled to take his spot in the bullpen.