Lindsey Vonn Injures Knee in Training Crash, Taken for Immediate MRI

It's unclear whether it was her surgically repaired right knee

Lindsey Vonn is hurting again.

The defending Olympic gold medalist in downhill skiing crashed during a training run this morning at Copper Mountain in Colorado and suffered an injury to one of her knees, according to SkiRacing.com. 

It hasn't been reported which knee suffered the brunt of the accident. Vonn had just started training again recently and was gearing up for a return to competition after shredding the MCL and ACL in her right knee at the World Championships in February, a serious injury that required surgery.

The 29-year-old athlete, who was supposed to make her racing comeback next week at the 2013 FIS Beaver Creek World Cup, was transported off the mountain by sled and taken to an area hospital, where she was scheduled to undergo an immediate MRI.

Vonn had just happily shared date-night pictures of her and boyfriend Tiger Woods at the Denver Broncos-Kansas City Chiefs game on Sunday night, and then on Monday she snapped a pic mid-run, tweeting, "Catching some air today in Downhill training @gopro #headwhatsyourlimit."

There's been no action on her Twitter account since.

"We have no reason to believe it's anything significant right now," U.S. Ski Team spokesman Tom Kelly told reporters Tuesday.

Vonn had said that she was hoping to be in top form by the start of the 2014 Winter Olympics in Sochi, Russia, in February so that she could defend her downhill title and improve on her bronze finish in the super-G.