KANSAS CITY, Mo. - Andy Pettitte suffered the first setback of his rehab, but it's too early to tell how significant it was.
Pettitte, on the DL with a strained left groin, was to throw a simulated game in Tampa Thursday but only did light throwing after experiencing some stiffness in his left hip flexor.
"[Wednesday] he said he was sitting on his couch, he got up and it felt stiff so he backed off [throwing], which was smart," manager Joe Girardi said. "If it takes a couple extra days, it takes an extra couple days."
If Pettitte throws Friday he'll probably be pushed to Wednesday for his first rehab appearance, which was supposed to take place Monday or Tuesday.
But that won't be pushed, either. "The last thing you want is a really big setback because then you're talking another month to six weeks," Girardi said.
Pettitte had considered himself ahead of schedule but sounded worried when he talked to Girardi. "I think there's some concern," Girardi said. "When you don't stay on schedule as a player you're going to be a little concerned. But I told him, 'Let's be cautious, let's be smart and if we have to push it back another day beside tomorrow, push it back. But we'll get you back.' "
Boss service news
Hal Steinbrenner, making his first public comments since the death of his father, told MLB.com after the third quarterly owners meetings in Minneapolis Wednesday that some kind of memorial service for The Boss was likely to take place Sept. 20 at the Stadium.
"We're still trying to pin it down, but I think it's going to be before the game on Sept. 20," Steinbrenner said.
He said he had been moved by the public's reaction since his father's death.
"It's always difficult when you lose a father," Hal said. "Even if it's something you know is going to happen, you're never fully prepared. The outpouring of sympathy has been outstanding. The media did a great job and the family has been really pleased with what has been said."
Alfredo Aceves will throw 35 pitches in his second rehab appearance Friday night for Double-A Trenton . . . Girardi said Francisco Cervelli, who caught last night, would catch Sunday, with Jorge Posada catching Friday night and Saturday night.