Tom Brady went down and stayed down earlier today after an incomplete sideline pass intended for Aaron Dobson. To make matters worse, Brady was seen clutching his left knee - the same knee that cost him the entire 2008 season.
While he would eventually get up, walk off the field under his own power, and return to practice a few plays later, he didn't remain under center for long. He eventually walked off the field, looking frequently at his knee, and ended up leaving practice with the team trainer.
I'd say there's absolutely no reason to panic right now, and that people tweak knees all the time, and that the odds are that Tommy B just landed wrong on his plant foot and strained one of the tendons or ligaments and so he left practice as a precautionary measure to make sure he didn't re-injure anything. And at the end of the day, all that is probably true. Odds are that it's nothing too serious and that the training staff is just making 100% sure Brady doesn't aggravate anything or do any more harm to what might be a very minor injury.
But that doesn't make me feel any better. Here's hoping we get some good news on the matter soon. Luckily for us, the Patriots are extremely good at divulging any and all injuries to the general public.
UPDATE: A fan watching practice captured the injury on video. You can check it out here: