Updated

Yankees pitcher Andy Pettitte had a setback in a simulated game Friday and will join the team Saturday in Kansas City for further evaluations.

Manager Joe Girardi said Pettitte could only push off at 75 percent in a 50-pitch simulated game at Tampa, Fla. Pettitte has not pitched since July 18 because of a strained left groin.

"It didn't go as well as we wanted," Girardi said Friday before a game against the Royals. "He just didn't feel like it's completely healed. He did not have full strength. Part of it is he feels a little something and is afraid to let it go.

"I think he did the right thing by not trying to push it. If he needs more time, he needs more time. He probably needs a little more rest. If that's what we have to do, that's what we have to do."

Pettitte was 11-2 with a 2.88 ERA in 18 starts before going on the disabled list.

"He's frustrated," Girardi said. "Would you expect anything else from him? I think he thinks it's a setback. "You know it's hard not to go out and do what you're accustomed to doing. It's hard to just sit there. It's probably driving him crazy."

He said Pettitte would not make a minor league rehab start Monday or Tuesday as originally planned and would need at least one more simulated game before going out on an assignment.

"We'll evaluate him when he gets here (Saturday) and decide the best day to do that," Girardi said. "We'll just give him treatment and make sure he kind of relaxes. He really wants to be back out there. I remember he was talking after a week or 10 days (after the injury) and said he would be back in three weeks. We told him this is probably would be five weeks because of what a pitcher has to do. He's got a lot of different movements and he can't control some of them."