Quintin Mikell, one of the St. Louis Rams' few defensive stalwarts in 2011, left their Thursday Night Football meeting with the Arizona Cardinals with a very scary-looking injury, taking a knee to the back of the helmet in the middle of the second quarter. Mikell was down on the field for several minutes, and surrounded by trainers, before he left the field under his own power.
Mikell's almost certainly out for the rest of the game, but things looked much worse than that before he started moving again. The Edward Jones Dome was silent, players were praying off to the side, and Mikell was invisible behind the Rams' staff. It was impossible to tell quite what was going on until the dome crowd, able to see Mikell moving better than the NFL Network cameras, erupted all at once.
There' was no immediate update on Quintin Mikell's condition, but in the moment seeing him walk off the field was just about enough. Given the NFL's continued work on preventing and minimizing the impact of head injuries, though, it seems reasonable to guess that Mikell will be unavailable Thursday.