Andy Pettitte completes bullpen test

CHICAGO -- The best news to come out of New York Yankees pitcher Andy Pettitte's bullpen session Friday afternoon, a session Joe Girardi termed "extremely important'' two days ago, is he was able to finish it.

The worst news is it's the first step in what could be a fairly lengthy rehabilitation process.

Under the watchful eyes of Girardi, pitching coach Dave Eiland and trainer Gene Monahan, Pettitte threw 25 pitches off the mound about four hours before the start of Friday night's Yankees-White Sox game. Afterward, both he and Girardi agreed progress had been made from the last time Pettitte attempted to throw a bullpen session at Yankee Stadium on Aug. 17.

After that one, Pettitte's next move was to an MRI tube at Columbia Presbyterian, which revealed a "small, persistent strain'' of his left groin, an injury that has kept him out since July 18.

Pettitte's next move is expected to be back to the mound for another bullpen session, perhaps as soon as Sunday.

"This was progress, this was definitely progress for us,'' Girardi said. "He's better than he was 10 days ago. I can't really tell you how much more or less, but today was a good day, that's all I can say.''

Pettitte's self-assessment was in line with his manager's. "It was good, I didn't have any discomfort at all," he said. "I feel like this thing's healing and now it's just a matter of building up my strength and the only way to do that is to get back out on the mound."

But Pettitte admitted, "I didn't push as hard as I could." Niether he nor Girardi could pinpoint when Pettitte's next bullpen session would be or provide a target date for his return or even for a rehabilitation start, let alone how many of those he would require before rejoining the active roster.

"You know, I really don't know," Girardi said. "I don't know if you need another bullpen after the next one. So much of it depends on how he feels and what he's able to throw if he throws on Sunday."

Based upon a best-case scenario in which Pettitte throws one more bullpen, followed by a simulated game and two rehab starts, he could return to action in mid-September. But Girardi raised the possibility Pettitte might need more rehab than that.

"The minimum, to me is you've got to face hitters at least twice [before being reactivated]," Girardi said. "Could there be a third time? Sure. Could there be a fourth time? Yes. I'm just not sure how long it's gonna take until he feels comfortable that he has the stuff to go out there and compete."

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

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