That's what WWE is saying, at least.
Last night (Sun., Nov. 20, 2011) at the Survivor Series pay-per-view in New York, Sin Cara did a spot that included his flipping over the top rope and landing onto Hunico on the outside.
Except it didn't go down that way.
Cara misjudged the jump and hit the top rope, landing slightly awkwardly on his knee. He immediately began clutching at it and he was attended to shortly after.
WWE.com is saying Cara suffered a ruptured patella tendon and he'll be out for a while:
According to WWE doctor Michael Sampson, Sin Cara suffered a patella tendon rupture when he jumped out of the ring during the Traditional Survivor Series Elimination Tag Team Match at Survivor Series.
"He's going to need surgery and be out [of action] for six to nine months for rehab," Sampson said.
This being the pro wrestling business, it's always safe to assume you're being worked but it's hard to tell here. After rewatching the fall, it didn't look like Cara landed bad enough on his knee to cause serious damage. He just botched the spot. (Hunico, by the way, laughably sold it anyway, even though he never got touched.)
Then again, he sold it like a legitimate injury, which is to say he didn't overact in the slightest. WWE is treating it like it's real and so are the major wrestling websites.
After the jump is a video that shows the spot and Cara landing badly on his left knee on the outside. Judge for yourself if you think it's legit. The jump happens at the 0:33 mark.