Denny Hamlin did his best to mask the pain on Friday.

Although he limped gingerly to his car for first practice Friday morning, he climbed into the No. 11 unassisted and went the distance during happy hour final practice in the afternoon. But it was obvious before qualifying that the lingering effects from ACL surgery on March 31 were taking a toll.

Hamlin winced after he climbed from the car and iced his knee in the garage. He sat cautiously on a table in the media center and looked paler than usual.

Not surprisingly, the question is whether Hamlin can complete the Subway Fresh Fit 600 at Phoenix International Raceway on Saturday.

"I don't know how far I'll go," Hamlin said. "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 pedal. That's a small issue, but we're going to do some things.

"We have some things that we're going to do that's going to make pain better and it's going to make range of motion better for tomorrow that we haven't done for today. Until we get to tomorrow, we really don't know where we stand."

Hamlin would not disclose what if any medication he was taking for pain. Hamlin simply said "physically the stuff I take is up to me. No one else needs to know." According to NASCAR spokesman Ramsey Poston, Hamlin has met all the necessary criteria through the sanctioning body's medical liaisons and Dr. David Black of Aegis Labs, which administers NASCAR's drug testing program. Additionally, Hamlin received medical clearance from his own doctors.

Poston added, "If Denny would be under any medications, it would be cleared through Dr. Black."

Hamlin reported "a lot of fluid build-up in the knee." He will have the knee drained Saturday morning, and stitches removed to assist flexibility and mobility.

As a precaution, Casey Mears is standing by this weekend to replace Hamlin.

Hamlin drove the car in the first practice to set a baseline, and was 10th on the speed chart after 11 laps. Then Mears jumped in to get acquainted with the cockpit.

"The seat is pretty tight for me in the shoulders," Mears said. "The belts were way too big for me. Denny is taller than me so we put about an inch spacer in the bottom of his seat. That makes the belts tight and gets my eye level where I need to be. It's pretty close -- other than my shoulders being tight, I'm pretty comfortable."

Hamlin finished first practice with a qualifying lap and topped the speed chart. He then ran final practice in its entirety, finishing 23rd- fastest.

"I was surprised to see him get in and run as many laps as he did, based on what I was hearing earlier in the week," Mears said. "I think he's feeling better than people thought. It's all going to depend on how much pain he's in or how uncomfortable he is (as to) whether or not I get in and race.

"He's feeling the same scenarios, he's going to feel. When you get in the race and you have to get more brake in sooner, harder, maybe he'll notice some things that he didn't notice in practice. But he's doing pretty well so far. We're just going to have to wait and see what his tolerance is going to be like."

Mears says what he's felt in the set-up car has been "pretty much identical" to Hamlin's. That should help the team make adjustments to the car should Mears have to relieve Hamlin.

As for Saturday's strategy, Hamlin expects to make a decision regarding how long he will race by lap 100 of the race's scheduled 375 laps.

"There's no reason, if I go past lap 100, that I decide to change and abort," Hamlin said. "I need to just tough it out at that point. We gotta do it early. And I'll know early what I've got.

"But, there's nothing that I can indicate -- there's so much different stuff that we're gonna do tomorrow morning to help this thing that I don't know how much better I'll feel tomorrow. But I know, as of today, there's no way I could do it."