Yankees manager Joe Girardi said that the injury is minor, but Pettitte was not happy with the decision to knock out his start. If it were the regular season, Girardi said, Pettitte would have been able to pitch.
"He felt something really, really, really mild the other day after his side session, so we decided to shut him down," Girardi said. "He felt nothing when he played catch, but we thought it's better to miss a start now than [if] something happens and you have to keep warming back up where you miss two or three [starts]. We're looking at the long term and not the short term."
The matter was discussed on Tuesday in a meeting that included general manager Brian Cashman. Instead of traveling to St. Petersburg, Pettitte stayed back in Tampa for hot and cold baths, light massages and stretching exercises.
"Our concern level is low," Cashman said. "He could have pitched [on Wednesday]. We talked about it and said, 'Why bother?'"
Pettitte reported four days late to camp due to his involvement in the congressional hearings concerning Roger Clemens, but he has said that his velocity and strength are close to where they should be at this time in the spring.
"Maybe I've been going a little too hard," Pettitte said. "I haven't tried to. Maybe I ramped my arm up a little bit quicker than I should have. I don't know, I'm just trying to figure out why I would have aggravated it."
Envisioned to be the Yankees' No. 2 starter, Girardi said that Pettitte's progress will not be affected by the missed start.
"We expect him to be capable to throw 90 or 95 pitches in his first start, where another guy might throw 100," Girardi said.
With a young starting core potentially involving Joba Chamberlain, Phil Hughes and Ian Kennedy in various roles, slotting a healthy Pettitte in every five days is of the utmost importance to the Yankees, whose only other veteran starter is 39-year-old Mike Mussina.
"I know what I'm going to do -- I've been doing it so long," Pettitte said. "I'm going to throw 200 innings, and I believe in this team. I'm going to win about 15 games. Really, to me, it's a given if you can toe the rubber. That's all I want to do."