Thursday night, something potentially devastating happened to the New York Yankees, their fans, and the entire game of baseball. Mariano Rivera was out shagging balls during pre-game batting practice, and he injured his knee in front of the wall. His facial expression was one of pure anguish, and he had to be carted off the field. We have a .gif and video for you, and we apologize for its being somewhat grisly. Don't say you weren't warned.
The early word - the very early word - is that Rivera has a "twisted right knee." However, "twisted" isn't a particularly medical term, and Rivera's been sent to an area hospital for an MRI. The Yankees will cross their fingers and hope the exam doesn't turn up significant damage. The great fear would be that Rivera did something to his ACL. All we can do for the time being is wait on the experts and the messengers.