Brady suffered the injury in his final season with the New England Patriots and it gradually worsened during his first year in Tampa, according to the report.
Brady, who was not listed on the injury report all season, underwent surgery to repair the knee in late February after leading the Buccaneers to a Super Bowl victory at age 43.
Brady has not discussed specifics about the surgery, saying only it was "pretty serious."
Brady suffered a torn anterior cruciate ligament in the same knee during Week 1 of the 2008 season.
Buccaneers quarterbacks coach Clyde Christensen said in June he believed Brady's knee injury last season was a "nagging nuisance" that affected him all season.
"I don't think he was 100 percent last year," Christensen said, relaying a conversation he had with Brady the morning after the Bucs won Super Bowl LV. "His quote, or close to a quote was, 'Hey, I'm gonna get my knee fixed up and I'm gonna be better next year and you're gonna be excited about that.'"
Brady, who will turn 44 on Aug. 3, wore a brace on his left knee during the Buccaneers' Super Bowl boat parade. But wearing the brace is not uncommon for Brady, who also wears it when golfing and during other recreational activities.
The seven-time Super Bowl winner was named Super Bowl MVP for the fifth time in his career after passing for 201 yards and three touchdowns in Tampa Bay's 31-9 victory over the Kansas City Chiefs.
Brady passed for 4,633 yards and 40 touchdowns while leading the Bucs to an 11-5 record during the regular season.