A person familiar with the injury says Patriots quarterback Tom Brady sprained his left knee in a practice Wednesday and his return is day to day.
The two-time league MVP limped off the field midway through New England's joint practice with the Tampa Bay Buccaneers.
Left tackle Nate Solder was pushed into Brady by Tampa Bay defensive end Adrian Clayborn. The two-time league MVP, entering his 14th NFL season, rocked backward on the ground and held his left knee. He went to the sideline, then returned for a few more plays before talking with coach Bill Belichick and leaving the field under his own power.
Brady tore the anterior cruciate ligament in his left knee in the 2008 season opener and missed the rest of the season. He has played every game since then.
"You've always got to stay away from the quarterback" in practice, Clayborn said. "You got a guy on his heels and my instinct is to keep going, so that's what I did."
The contact came after Brady threw a long incompletion down the right sideline toward rookie Aaron Dobson.
"We're always working to protect," Solder said. "I'll have to see what happened on the film. I screwed some things up here and there."
After Brady left the field, Ryan Mallett played with the first offensive unit and Tim Tebow played with the second team. Mallett threw an interception soon after taking over. In his first series after Brady left, Tebow completed three of seven passes.
"I'm just trying to do my job," Mallett said. "I'm sure Tom will be fine and we'll just go on."
Tebow left practice without speaking with reporters.
"Anytime anybody, especially a teammate, goes down it's a dark cloud. It's unfortunate," Patriots