Pettitte was removed in the sixth inning Friday night against the Cleveland Indians. The left-hander strained his back earlier in the week against the Rangers and slipped on the wet mound a couple of times Friday.
Pettitte played catch Saturday, according to manager Joe Girardi.
"He's still on target," Girardi said. "The progress he made overnight makes me feel good."
Girardi thinks Pettitte might have been over-striding in his delivery Friday night. Pettitte bent over after throwing a pitch in the fourth inning, but remained in the game. He started the sixth by allowing a single to Mark DeRosa and walking Ben Francisco. After Pettitte went to a 2-0 count on Jamey Carroll, Girardi and assistant athletic trainer Steve Donohue went to the mound. Pettitte was removed after a brief discussion.
Pettitte, charged with one run in five-plus innings, got the win in the Yankees' 3-1 victory, raising his record to 5-1. He allowed six hits, walked five and struck out one.
If Pettitte, who turns 37 next month, can't pitch Wednesday, right-hander Chien-Ming Wang might make the start. Wang has made two relief appearances since coming off the disabled list. He began the season in the rotation, but was 0-3 with a 34.50 ERA in three starts before going on the DL with weakness in his hips.
"Hypothetically, he could make the start, but you never know," Girardi said. "We might have to use him in relief before that."
Wang pitched two scoreless innings against the Rangers on Wednesday.