Sources: JR Hildebrand tears ACL

FORT WORTH, Texas -- JR Hildebrand, who crashed while leading on the last lap of the Indianapolis 500 two weeks ago, suffered a torn ACL in his left knee Wednesday afternoon at Texas Motor Speedway, sources confirmed Thursday.

The only statement by Panther Racing officials is that Hildebrand suffered a knee injury, but they did not want to comment further.

Hildebrand is still expected to compete in the Twin 275 IndyCar Series races Saturday night at TMS.

"Obviously it's a hassle, but I've got good means of dealing with it this weekend and it's not going to be an issue down the road," Hildebrand said. "This kind of stuff happens to lots of athletes, and I'm sure if I was a running back for the Indianapolis Colts I'd be having some problems, but luckily it's not going to have any affect on me driving the race car."

If a replacement is needed, Panther Racing said it has Buddy Rice, the 2004 Indy 500 winner, on standby in Texas.

Hildebrand was taking part in a TMS promotion at the track Wednesday, called "Driven To Fitness," a boot-camp style obstacle course to prove race car drivers are athletes. Drivers Ryan Briscoe and Will Power also participated in the promotion. Track star and four-time Olympic gold medalist Michael Johnson was the instructor for the drivers.

The final test was a hurdles race, but Hildebrand's knee hit the wood on the final hurdle. TMS officials took Hildebrand to the infield care center, where he learned of the ACL tear.

Hildebrand, a 23-year-old IndyCar rookie from Sausalito, Calif., was in position to win the Indy 500 last month before slamming into the Turn 4 wall heading to the checkered flag. Dan Wheldon passed him for the victory.

In Texas, Hildebrand hoped to start a new chapter in his racing career. But the knee injury won't help matters, even if Hildebrand is trying to keep this race business as usual.

"I think the Texas race is going to be fun," he said. "Panther brings a good package here every year and I think the two-race format is going to be pretty cool. I'm not sure what to make of it honestly in terms of how aggressive everybody will be going into it. This is the perfect type of track to have a more random grid like what you'll see in the second race and that will make for better racing because here you can pass and use the high line to get around people."

Terry Blount is a senior writer for ESPN.com. Information from the Associated Press was used in this report.