Andy Pettitte out until September

NEW YORK -- New York Yankees starting pitcher Andy Pettitte will not be ready to return to the mound until the first week of September at the earliest, and more likely the middle of the month, which could compromise his ability to be at his best for the postseason.

"I think if you get into the third week of September, and we haven't gotten him back, you'd be somewhat concerned," manager Joe Girardi said before Wednesday night's Yankees-Tigers game at Yankee Stadium.

Pettitte's rehab of the left groin muscle he strained July 18 was shut down for a week by the Yankees training staff Tuesday after an MRI showed that the injury still had not healed.

"To say I'm frustrated, that's an understatement," Pettitte said. "I'm trying to stay as positive as I can, but I want to pitch. I just want to get back and I want to pitch and I want to be healthy."

Pettitte felt pain during a bullpen session Tuesday when, after playing catch in the outfield and then throwing with diminished intensity first off a half mound and then a full mound in the bullpen, he tried to cut loose as if pitching in an actual game.

"When I tried to go, to throw like I was trying to get a batter out, it would grab me," he said. "I felt actually like I was being a weenie out there, like I could pitch through this."

But Pettitte was overruled by pitching coach Dave Eiland and team physician Dr. Chris Ahmad, who sent him to Columbia Presbyterian for the MRI.

"Doc said, 'Let's do it so you can know if you're healed and you can just push through it,'" Pettitte said. "It's a good thing we got it because it told me I could hurt myself if I tried to push through it."

Being Pettitte, he blamed himself for pushing too hard in attempting to come back sooner than expected. "It's my downfall, the anticipation and expectations I have," he said. "I literally felt I was gonna be ready to pitch against Boston maybe, or in Kansas City on the weekend, no doubt about it. Obviously, that was last week and I'm sitting here and I'm not gonna be ready to get back on the mound for another week. A lot of stuff is going through my head as we get to the end of the season here."

Some of that "stuff" included the frightening prospect that after posting the best start of his career, 11-2 with a 2.88 ERA, Pettitte might not be able to pitch again this season.

"Of course that crosses your mind," he said. "I'm sure age has a lot to do with it. I got a lot of wear and tear on my body since 10 years ago or nine years ago the last time I did this. I'm sure that has a lot to do with this also."

Pettitte went on the disabled list July 20, two days after leaving a start against the Tampa Bay Rays in the third inning after suffering the injury on a pitch. At the time, the Yankees projected Pettitte would be out four to five weeks. Pettitte insisted his absence would be closer to three. Now, it turns out both sides were wrong.

"It's going to end up, right now, at least seven weeks, and that's longer than we anticipated," Girardi said.

And that is the best-case scenario, which assumes that the prescribed week of rest -- during which Pettitte will still be allowed to play catch -- is followed by a normal rehab progression, meaning long toss followed by a bullpen session followed by a simulated game and then at least one rehab start.

Even Girardi seemed to think that blueprint overly optimistic. "The last thing you would want is for him to come back and say, you know what, I feel like I can only give you 60 pitches," Girardi said. "That's not really going to help us. My thought process is he might have to make two [rehab starts]."

Pettitte is notoriously impatient when coming back from injury, but seemed resigned Wednesday to having to curtail his activity if he hopes to come back in time to be effective in October.

"Mentally, I'm just gonna try to stay as positive as I can, and whatever it is, it is," he said. "I'm gonna go with it and prepare as good as I can and I'm gonna just give it everything I got to get ready and help us get to the playoffs, hopefully."

Wallace Matthews covers the Yankees for ESPNNewYork.com. Follow him on Twitter.

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