Pettitte, 38, told the Yankees after the American League Championship Series not to count on his return and that he was leaning toward retirement, saying he needed to spend more time with his family in Texas.
"Andy has told us he's not in," general manager Brian Cashman said on Wednesday. "He told us that right after we got knocked out by Texas. He told us if he ever changes his mind, he'll let us know."
But Pettitte has continued to leave the door open at least a sliver, with his decision still not set in stone despite the report date for pitchers and catchers quickly approaching.
"Basically, the advice that I've given him is: 'Just think about it, talk to your wife [Laura] about it,'" Girardi said. "There's no rush, there really isn't, because he is training."
Girardi said that he left his last conversation with Pettitte still "mulling over his options." He did not know if there was a cutoff date for Pettitte to make a decision.
"Andy needs to do what's right for him," Girardi said. "That's the most important thing, and I respect that. That's not an easy decision to make."
Though not specifically voiced by the Yankees, there is a thought that Pettitte could return at a later date, as Roger Clemens did by joining the team in June 2007, when the starting rotation floundered.
Cashman said that it was "not even sensible for me to speculate" about such a scenario, and said that there was no reason to call Pettitte and try to talk him into pitching.
"He's not open to persuasion," Cashman said. "He's made a decision and it's more about if he changes his mind. I don't want to change someone's heart. He knows at the same time how dedicated, how committed, how much effort it takes.
"His heart has got to be in it, he's got to be all in. And if it's not, then it's in everybody's best interest for him not to play, including himself. Only he can make that decision."
For now, Girardi said he is looking at his rotation on paper without Pettitte, but holding out hope that won't have to be the case in three weeks.
"We always have hope. I always think positive," Girardi said. "I hope he does come back -- who wouldn't want Andy Pettitte to come back? But you do have to kind of prepare like he's not coming back."