USC QB Mark Sanchez went down at the start of practice on Friday in Los Angeles with a knee injury.

(Injury or no, Mark Sanchez makes people touch themselves)

From Gary Klein of the LOS ANGELES TIMES:

A witness reported seeing Sanchez doing a carioca shuffle. He then went to throw a football, put weight on his left knee and collapsed.

Sanchez was helped to the trainers’ table, where ice was administered and his jersey and shoulder pads were removed. He was then carted to the locker room and was then taken for x-rays.

Strangely, despite a full complement of beat reporters (LAT, LADN, OCR) at USC football practice, apparently none saw the injury happen. More importantly, just what the hell is a “carioca shuffle“?

Why, let Fred Astaire and Ginger Rogers show you: