BRISTOL, Tennessee (AP) -- There was a time in NASCAR when skipping a race because of illness or injury was simply not considered. Rather than sit out with swollen eyes, Ricky Rudd used tape to keep them open. Richard Petty ran three races hiding a broken neck from NASCAR officials.
That bravado -- foolishness? -- in drivers is no more.
Denny Hamlin became the fourth Sprint Cup Series driver to require a replacement when he pulled out of Sunday's race at Bristol Motor Speedway with neck spasms. Hamlin felt fine at the start but said he felt something pop around Lap 12. Rain 10 laps later gave him a nearly four-hour delay to work on the pain, but he turned his car over to 18-year-old Erik Jones when the race resumed.
"I'm no use to the team like this," Hamlin said from the garage. "In this win-and-you're-in format, there's no point in me being out there if I can't win."
Indeed, changes to the championship format have given drivers the flexibility to admit they are not healthy enough to drive. NASCAR last season expanded the Chase for the Sprint Cup championship field to 16 slots and said a win would automatically ensure a driver a berth in the playoffs.
So when Hamlin was parked one race last March by medical officials who said an issue with his eye was not suitable for racing, there was no panic: All he had to do was collect a victory by the 26th race of the season to remain eligible for championship competition.
Before the Chase, which began in 2004 and has steadily evolved, missing a race would ruin a driver's championship chances. Sometimes it could even cost him his job if the team owner or sponsor balked at his absence.
The system caused Dale Earnhardt Jr. to conceal a concussion early in his career and led to countless other hidden ailments from drivers too determined to play through the pain.
Hamlin, who picked up his Chase-qualifying win last month, saw no need for such heroics. Nor did car owner Joe Gibbs, who flew Jones in from North Carolina during the rain delay but almost balked at putting him in his first career Cup race when he arrived just five minutes before the rain delay ended.
Gibbs said Hamlin was willing to get back into his car and drive at least until the first caution.
"He was honest with me. He said, 'I'm not 100 percent,'" Gibbs said. "But you don't want somebody, an athlete like that, getting in a car like that. So as we talked it over, I just said, 'Hey, look, let's don't do this. Let's put Erik in there.'
"I think we made the right decision. Hopefully with that, we didn't aggravate anything else, so hopefully he gets some treatment, and then we'll be good to go next week."
Kyle Busch, Hamlin's JGR teammate, has missed the first eight races this year after breaking his right leg and left foot in a crash the day before the Daytona 500. Although he does not know when he'll return, he said last week he was holding out hope he'd receive a medical waiver from NASCAR that would make him eligible for the Chase if he qualified.
Brian Vickers is sidelined indefinitely for treatment of blood clots, but NASCAR earlier this year granted him a waiver when he missed the first two races of the season as he recovered from offseason heart surgery.
Kyle Larson was not allowed to race last month at Martinsville Speedway after fainting a day earlier during an appearance. It took nearly three days in the hospital for dehydration to be diagnosed, and he's now seeking a win that will get him into the Chase.
Although Hamlin seemed to receive some social media backlash over his decision not to race -- fans complained the old guard was a far tougher bunch, that sitting out with neck spasms appeared awfully soft -- he played by the rules of the system.
And make no mistake that it's a good system. Regular-season points are no longer the end all of a driver's season, and it allows NASCAR to have a far higher standard of safety for its competitors.
Drivers can't race with a concussion anymore, and obtaining medical clearance to compete is not the slam dunk it once was.
Hamlin, who appeared to bristle Monday at a tweet that seemed to suggest he wasn't as tough as the late Dale Earnhardt, didn't need to make a hard decision Sunday. When he spoke in the garage, he was clearly stiff and struggling to turn his head -- not the best condition to attempt to complete a race.
He's got a new championship format to thank for not forcing him to get back behind the wheel.