After his next bullpen session was pushed back, Zach Greinke may not be ready for Opening Day with the Arizona Diamondbacks.

Greinke left Wednesday's exhibition game with right groin tightness.

"Obviously when you're talking about potentially pushing him back and not having him ready for Opening Day, my concern level goes up," Torey Lovullo said. "But I know it's a situation that's going to be a very positive outcome. ... I feel very strongly that he'll be in there as quickly as he possibly can."

Greinke said that he doesn't expect the injury to be "a long-term thing."