FONTANA, Calif. (AP) -- Denny Hamlin missed Sunday's race at Auto Club Speedway with a sinus infection that led to vision problems.
Hamlin was ruled out of his Joe Gibbs Racing Toyota about 30 minutes before the green flag at the track where he crashed on the final lap of last year's race.
''It's not just a headache. It's a lot more serious than that. He was actually losing vision his eye,'' crew chief Darian Grubb told MRN.com and NASCAR.com after Sunday's race.
Hamlin was released from a hospital after the race ended. He will be evaluated again in the next week back home in Charlotte.
Sam Hornish Jr. finished 17th as the late replacement in the No. 11 car for Hamlin, who had hoped for redemption at Fontana after leaving being airlifted away from the track with a broken vertebra last year.
''So disappointed that I can't compete today,'' Hamlin said in a post on his Twitter account. ''Sorry to all my fans. Thought we had a car that could win today.''
Hamlin was not medically cleared by a NASCAR doctor to race and was told to go to the hospital, team President J.D. Gibbs said.
Although team owner Joe Gibbs said after the race Hamlin was still undergoing tests and he didn't know when they'd have results, Grubb told the two media outlets after the race that Hamlin was still hospitalized.
''The last I'd heard, his vision was getting worse and the pain was getting worse,'' Grubb told the two media outlets. ''It got to where he couldn't see and was having trouble with the vision in his left eye because of the pressure and everything that was going on. At that point, NASCAR did some testing and he could not follow the finger going by his eyes as he should have been.
''They weren't going to let him go.''
Hamlin wore dark sunglasses in the indoor driver meeting two hours before the race.
''He held his head and said his head was hurting so bad. He was having trouble seeing,'' Grubb said. ''You could tell the worry in his face, he was really upset.''
Hornish is scheduled to drive seven races for Joe Gibbs Racing this season in the Nationwide Series, but he was on hand at Fontana as Matt Kenseth's standby driver as Kenseth awaits the birth of his fourth child.
Hornish and Hamlin are both roughly 6 feet tall, so few adjustments had to be made for the seat or pedals in Hamlin's car. Grubb said the team had no time to change the seat for Hornish, who started last in the No. 11 Toyota and finished 17th.
Hamlin's scratch was a huge disappointment at Fontana for the second straight year.
Hamlin and Logano, his former teammate and unfriendly rival, were racing for the lead down the backstretch on the last lap last year when they collided, sending Hamlin hard into the inside wall. Hamlin got out of his car and collapsed onto the asphalt, and was eventually airlifted to the hospital due to traffic.
Hamlin missed most of five races with a broken vertebra, and the injury left him in back pain for months. After an offseason recovery from his back woes, he had hoped to get back to full strength along with his team this season.
Hamlin was seventh in the points standings headed into Sunday's race and dropped to 11th after sitting out. Drivers can still qualify for the Chase for the Sprint Cup championship so long as they qualify their car - as Hamlin did on Friday - or race in every one of the first 26 races.
Either way, Hamlin would receive a medical exemption from NASCAR since he was not cleared to drive by a doctor.