McClanahan was diagnosed with a left shoulder impingement after being scratched from Tuesday's start at Miami, pending further imaging, Tricia Whitaker of Bally Sports Sun reports.
McClanahan was on track to start Tuesday before the injury flared up while he was warming up in the bullpen. The left-hander, who is in the mix for the AL Cy Young Award, should be considered day-to-day as he continues to be evaluated, and it's unclear if the issue will affect his availability for the next turn through the rotation.