CINCINNATI -- Reds right-hander Edinson Volquez had another major setback on Friday in his rehabilitation from elbow tendinitis. Volquez had to shut down his simulated game after he experienced pain.

This was supposed to be the final step for Volquez in his recovery after he had completed three bullpen sessions with no pain. Now he likely will have to go back to the start of the rehab program.

Reds manager Dusty Baker said he didn't get a chance to see the session because he was dealing with all of the trades.

"My trainer told me it was a 50-50 chance it could happen," Baker said. "So now it's back to the drawing board again. That's something I wasn't expecting or hoping for."

Baker said Volquez told him he felt tightness -- not in the same area, but in the same muscle. Whether Volquez will need surgery remains to be seen.

"What's best for him now and in the future is getting him back healthy for next year," Baker said. "I'm very concerned, but I also have full confidence in [Reds medical director] Dr. [Timothy] Kremchek and full confidence in modern medicine."