May is on the disabled list at Low-A Great Lakes with an undisclosed injury.
He allowed one run on six hits and zero walks while striking out four in six innings in his start on Aug. 4, but must have suffered some sort of injury in that outing. May has been a revelation this year, posting a 3.21 FIP, 1.21 WHIP and a 102:24 K:BB in 108 innings as a 19-year-old in the Midwest League.