RG3 Backs Lindsey Vonn’s Olympic Push, Would Be 'Greatest Story Ever'

Robert Griffin III is tipping his cap to Lindsey Vonn's wild Olympic gamble ... saying if she pulls off gold with a ruptured ACL, Hollywood better start casting ASAP.

After all, he knows a thing or two about ACL injuries, having torn his twice -- once in college at Baylor and again in the NFL with Washington.

TMZ Sports asked the former QB about Vonn's decision to compete in the Winter Games despite the injury ... and he says he can relate to her all-gas-no-brakes mindset.

"Having done that before, you can get back to similar strength, similar flexibility before you have the surgery," Griffin said. "But your knee is going to be in a much more compromised position. So Lindsey is going to do what she wants to do."

"She wants to go attack it and try it out, and if the doctors clear, then there’s nothing anyone can do about it."

Vonn, of course, has never been known for playing it safe. Griffin praised her fearless approach ... calling it inspirational and a reminder of how far elite competitors are willing to push their bodies for greatness.

He also made a broader point that if women can handle childbirth, competing at an elite level with catastrophic knee damage shows just how tough they are.

"I think it’s inspiring to a lot of people," RG3 said. "And I think that’s what she's trying to do. She's going to go out there and try to win. And if she does, it’s going to be one of the greatest stories ever written."

And RG3 didn’t stop there ... he predicted if Vonn somehow skis her way to a gold medal, the story would be so legendary it’d demand a movie adaptation.

Griffin -- and plenty more Americans -- will be locked in watching ... hoping Vonn and Team USA bring home hardware.