Walker felt a pinch in his left shoulder during a swing in Saturday's loss to the Blue Jays, Anthony DiComo of MLB.com reports.
Walker struggled for the second consecutive start, as he allowed six earned runs on eight hits and two walks across four innings to take the loss. However, the bigger problem could be the injury he picked up during the outing. After the game, Walker downplayed the issue and would not tell reporters the nature of the injury. However, manager Luis Rojas disclosed the shoulder pain. At this point, there seems to be minimal concern from both the player and team, meaning Walker should still be able to make his next turn through the rotation if no further information emerges.