As if that wasn't enough, he somehow managed to win, too.
Competing with a brace on his ankle, Keselowski sped off on the final restart late in the race to pick up his second victory of the season. He gingerly climbed out of his car to celebrate with his crew in Victory Lane.
"It doesn't feel good, but I'll be all right," he said.
Keselowski was an unlikely winner after he crashed head-on into a wall on Wednesday during a test session at Road Atlanta. He slammed a section of wall at 100 mph and was forced out of the Nationwide Series race.
He insisted during practice this weekend he wouldn't leave the No. 2 Dodge, no matter how much pain he was in.
Wasn't necessary. Keselowski had some rest during a 1 hour, 40-minute rain delay.
"I was amazed he raced the full race," third-place finisher Kurt Busch said.
Keselowski's victory thrust him into prime position to claim one of two wild-card spots available for the Chase for the championship. The top two drivers with the most victories in 11th to 20th place earn a wild-card spot for the playoffs.
Keselowski, in 18th place, is the only one of the wild-card contenders with two victories. Only five races remain until the field is set. The top 10 drivers in the points standings automatically qualify.
Keselowski posted several updates on his injury this week on his Twitter page, including two photos that showed a swollen ankle and an abrasion on his foot. His broken left ankle ballooned to the size of a softball, and he needed a left shoe a size larger than his right one.
"There's no good time, but this is certainly the worst time," he said Friday.
No way. Keselowski won his third career Cup race and first since he won in June at Kansas.
Kyle Busch was second, Jimmie Johnson fourth and Ryan Newman fifth.
Kurt Busch and Johnson had a heated exchange after the race because of some last-lap contact and had to be separated by their crews. The star drivers took turns bumping into each other on the final lap. Busch said it was simply hard racing and Johnson, the five-time defending Cup champion, overreacted.
"You want to race, let's race," Busch said. "I raced him smart, raced him clean, and he wants to come back here and (complain) about it. Why can't we race each other like this and put on a show for the fans?"
There was a racing tripleheader after rain halted the Trucks Series race on Saturday and wiped out the ARCA race. Kevin Harvick won the Trucks race, Ty Dillon took ARCA and Keselowski capped it all with his gutsy performance.
"There are moments in our sport that need to be documented as an `Iron Man' type of day," Kurt Busch said. "It's amazing what the body can do."
Rain hit Pocono hard the last two days and when the red flag came on lap 125, Joey Logano had the lead. He took a break in the ESPN broadcast booth where he was asked if he wanted the rain to stop or keep coming.
"I think it's a dumb question," he said.
Logano faded hard and finished 26th. Points leader Carl Edwards, who signed a multiyear extension with Roush Fenway Racing, was seventh.
Once the rain stopped, Kyle Busch build a sizable lead until it was wiped out on a final caution.
That was the opening Keselowski needed and he took advantage - even with only one good ankle.