The Athletics placed Medina on the 15-day injured list Monday due to a blister on his right index finger.
Medina presumably picked up the injury during his most recent start versus the Orioles on Friday, when he lasted just three innings while giving up four runs (three earned) on five hits. Reliever Spencer Patton was brought up from Triple-A Las Vegas to take Medina's place on the roster. Medina's placement on the IL is retroactive to Saturday, so he won't be eligible for activation until Sept. 3.