BOSTON: NFL MVP Tom Brady went from the disappointment of a Super Bowl loss to the devastation of a knee injury in Sunday's season-opener that could keep him out for the rest of the season.

After missing the entire preseason with an unspecified foot injury, Brady left New England's game against the Kansas City Chiefs in the first quarter after being hit on the left leg by Chiefs safety Bernard Pollard. Coach Bill Belichick provided no information on the injury, but Pollard had a diagnosis of his own.

"He was in a lot of pain," he said. "When you hear a scream, you know that."