NEW YORK -- When Ian Kennedy complained of stiffness in his upper back, the Yankees didn't hesitate to make a substitution. With a seven-time Cy Young Award winner waiting in the wings, the decision was easy.
Try again. Roger Clemens' time as New York's probable starter for Saturday's matinee against Toronto lasted but a few hours, as the 45-year-old right-hander tweaked his left hamstring during cardio workouts and will also be scratched.
"When he was doing his exercises, he felt a little something in his leg," said Yankees manager Joe Torre. "He went out and threw and felt OK, but we decided just to push him back until Monday. ... He said it felt OK, but it was pretty much just our decision."
Instead of Clemens, the Yankees will give the ball to 21-year-old rookie Phil Hughes. For Clemens, what would have been his 18th start of the season will tentatively be pushed back to Monday, a series finale against Toronto, though the Yankees are planning to proceed cautiously.
Pitching coach Ron Guidry said that Clemens felt a "tweak" in his left hamstring while working out on his running program during the Yankees' off-day Thursday. Clemens threw a side session at Yankee Stadium on Friday and told coaches that he did not feel anything while throwing, but the Yankees have decided to err on the side of caution.
Clemens is 6-6 with a 4.18 ERA in 99 innings this season for New York, and the club is looking for him to make one or two more starts in the regular season. Whether the start comes on Monday against Toronto or Tuesday at Tampa Bay would be of little difference, Guidry said.
"The thing is, we need you for one more real good one, but we want you healthy," Guidry said, recalling his conversation with Clemens. "What if you go out there [on Saturday] and you think it's OK, but you start and all of a sudden, boom, it pops? Now we lose you altogether. We've got enough pitchers here to pitch. Let's make sure we don't say, 'OK, we have to have you.' It's not that imperative right now."
Guidry said that because the left leg is Clemens' landing leg in his delivery, the leg takes on much more stress because it is always extended. Tentatively, Hughes will pitch on Saturday against Toronto, and right-hander Mike Mussina will go on Sunday; if Clemens is unable to pitch on Monday, the Yankees are likely to select a starter from their crop of September callups.
"We're just taking the safe route," Torre said. "That's what happens. It's at a situation where the off-day that we had will help us, because we've got guys rested."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.