NASCAR driver Denny Hamlin gingerly walked through the garage area Thursday, doing everything he could to prevent more back spasms.

He put practice on hold, too.

Hamlin sat out two sessions for Saturday night's Sprint Cup race at Daytona International Speedway because of back spasms and decided not to drive in Friday's Nationwide race.

Hamlin said the spams began Sunday, a day after 400 miles over rough pavement at Kentucky Speedway, and got to the point where he could barely move around. He treated the injury with ice, stimulation and a pain-killing injection, and said that he will eventually need surgery.

In hopes of making as close to a full recovery as possible by Saturday's race, Hamlin and his Joe Gibbs Racing team opted to keep him out of the car except when necessary Thursday and Friday. They realized that one wreck could wipe out days of progress.

"I've made such decent to good progress through this week that you don't want to give that up by getting in a wreck or jeopardizing being able to start the Cup race," said Hamlin, who ranks fifth in Cup points. "We decided to sit everything out until I'm absolutely needed, and we'll take it from there."

Skipping practice at Daytona is easier than at other tracks because drivers have little impact on the car's performance around the famed superspeedway, a place where drivers often hold the throttle wide open.

JGR teammate Kyle Busch turned three laps in Hamlin's No. 18 Toyota, giving crewmembers a gauge on the car's setup. Hamlin expects to get behind the wheel Friday for qualifying. But he's unlikely to do much else.

"I'm just now starting to get mobile again and being able to get around," Hamlin said. "We don't want to set any of that back by sitting down (in the car) any longer than I have to."

Hamlin said he could have driven had it been necessary and probably would have at other tracks. He is so confident that his back will be fine by Saturday night that he didn't even line up a relief driver.

"If something were to happen, there would be somebody around that could help," he said. "I do plan on starting. I could probably do it today if I had to."

Spasms have plagued Hamlin since 2008 — he blames his father for inheriting back problems — but the latest ones top the list.

"There's some torn disk. There's some bulging disk. There's a lot of different thing that have just happened over time," Hamlin said. "It's just gotten progressively worse."

His love of basketball and golf might put extra strain on his back.

"It very well could," he said. "There's always a chance of that. Those are things that I work really hard to stretch. There's reasons why it's happening and getting worse, even before I picked up golf and basketball. I don't directly link it to that."

Nonetheless, Hamlin said he will "definitely have to tame it down" after his latest relapse.

He plans to start strengthening his back muscles next week in hopes of recovering and being better equipped to handle another episode.

"Now that we have diagnosed it, we can make it better," he said.