Tillman will not make his scheduled start Sunday due to lower back stiffness, Roch Kubatko of MASN Sports reports. The severity of Tillman's injury is uncertain, but the setback will prevent him from taking the mound Sunday. The Orioles have not announced who will start in Tillman's place, but they are considering going with one of relievers Mike Wright or T.J. McFarland, or bringing up a starter from Triple-A.