Pettitte had been scheduled to pitch Saturday before having that start pushed back to either Tuesday or Wednesday, and the team is now giving the 40-year-old even more time to ensure he's healthy.
"He's better but instead of saying let's throw a bullpen today and see how he feels and then if he has a setback then Friday becomes jeopardized," Yankees manager Joe Girardi said. "We thought let's give him until Tuesday, we feel everything will be cleared up and then we'll have him on the mound."
Pettitte had been scheduled to throw a bullpen session Sunday and will now throw it Tuesday. While Pettitte understands why he's was delayed, he'd rather pitch as scheduled.
"I'm on board to a certain extent," Pettitte said before the Yankees faced the Orioles. "I just want to pitch. I understand it."
The southpaw first noticed the back spasms in his start against Cleveland on April 9, although he managed to work through seven innings. He felt sore the following day, but felt great during his workout April 11. That night, though, Pettitte's back locked up on him, specifically in his lower back. The team immediately decided to push him back to give him extra rest.
Pettitte has battled injuries the last few years as he last pitched a full season's worth of games in 2009. He had 21 starts in 2010, and after returning from retirement last season, he pitched 12 games as a fractured fibula cost sidelined him for several months. Pettitte is 2-0 with a 1.20 ERA in two starts this year.
"It's frustrating," Pettitte said Friday. "I had seven weeks of spring training, not one problem. It is a worry for me because I want to be healthy and I want to make my starts, but I also know that it's also a muscle spasm and if it goes away I'm going to be fine to pitch."
Yankees center fielder Curtis Granderson appeared at Yankee Stadium on Sunday and shagged some balls in the outfield. The outfielder, who is on the disabled list after breaking his forearm on Feb. 24, threw on Thursday and Saturday, his first times since the injury.
Granderson told the Associated Press that he may have been able to start swinging this week, but he has yet to do so. The lack of swinging doesn't mean Granderson had a setback, but is instead going through all the proper steps during his recovery.
"They want the throwing all to be first. The swinging was something that could happen, the timetable of when was to be determined," Granderson said. "After further considerations with the doctors and trainer here and in Florida, it was once the throwing was good to go, we'll start swinging."
While May 1 had been mentioned as a possible return date for Granderson, Girardi believes that might be wishful thinking. Granderson said he still needs to play games, get at-bats and play back-to-back nine-inning games before returning. Yankees hitting coach Kevin Long told Granderson that he needs to get about 50 to 70 at-bats during his rehab.
"I think (May 1) is probably maybe a little quick. I don't know," Girardi said. "You basically have to see how a guy's rehab goes. He hasn't swung a bat yet and today's April 14. Until he swings a bat we're not really going to have an idea."
In Sunday's series finale against Baltimore, the Yankees will be without infielder Eduardo Nunez, who will miss his second straight game after being hit by a pitch and suffering a right wrist contusion Friday.
Nunez threw Sunday and will start swinging Monday in hopes of a return Tuesday against Arizona. The infielder said he could be available for pinch-running or defense if needed on Sunday night, and said he's feeling better.