The Joe Gibbs Racing driver, who claimed victory at Martinsville two weeks ago before having surgery for a torn anterior cruciate ligament, topped the first practice session of the weekend at Phoenix, but he doesn't feel he is ready to complete the 375 scheduled laps on Saturday afternoon.
Hamlin is set to get some treatment in the morning ahead of the race in order to be in the best shape possible to start the race, but he is not sure about that being enough for him to be able to finish the race.
"There's so much different stuff that we're going to do tomorrow morning to help this thing, that I don't know how much better I will feel tomorrow," Hamlin said. "But I know as of today, there is no way I could do it."
Hamlin will have Casey Mears on standby as his relief driver in case he feels unable to continue to race all the way to the chequered flag. The Californian drove some laps in the opening practice of the day and actually tested a driver change.
According to NASCAR rules, if a driver starts a race, even if he is not the one behind the wheel when crossing the finish-line, he still gets credited with the points given to his position.
"I don't know how far I'll go," Hamlin admitted. "It definitely aches quite a bit. And the problem is range of motion - I can't get my knee bent far enough to put it on top of the [brake] pedal."
Hamlin will start the race from 26th place on the grid following a disappointing qualifying effort, although he seems most frustrated by not having recovered as much as he had expected.
"It's frustrating because your mind wants your leg to do one thing, but your body won't do it," said Hamlin. "It's a delayed reaction every time I want to do something. I don't feel that I'm doing my best out there, and that's frustrating from my standpoint.
"I'll do whatever I can. That's all I can do. I've done everything I was supposed to do and then some. If it's not enough time, then it's not enough time."
Salgado - Rafa ready for RealHamlin not ready for race distance
