Wainwright (elbow) threw five innings in a rehab start for Double-A Springfield, allowing no runs on two hits and striking out two batters.
Wainwright was placed on the disabled list with elbow inflammation in late April. Prior to the injury, he had a 3.45 ERA through three starts, but a discouraging 12:8 K:BB and an 81.9 percent left on base rate suggested that some regression is in order. Whether or not he'll need another rehab start or two is not yet clear.