Nate Solder has said that he is not sure how he came to collide with teammate Tom Brady during a joint practice with the Tampa Bay Buccaneers yesterday.

The New England Patriots quarterback limped out of the session, having been knocked down by Solder, who was battling with Buccaneers defensive end Adrian Clayborn.

The offensive tackle told the Patriots' website: "I don't know what happened. I'll have to see it on film. We're always working to protect you know, I screwed some things up here and there. We'll work to improve it.

"Anytime someone goes down, we worry about it. So, we'll see what happened. I don't know at this point. There were a few different things that happened. I'll have to see it."

Clayborn added: "I bull rushed the tackle and apparently he tripped on Brady and fell on him. You always have to stay away from the quarterback, but if you get a guy on his heels, my instinct is to keep going. And that's what I did."

The Patriots have confirmed that Brady sustained a knee injury as a result, but it is not thought to be serious.