Mayo, entering his seventh season with the team, missed 10 games last season after tearing his pectoral muscle. The Patriots struggled defensively and ranked 26th in the league in yards allowed last season.
Belichick expects Mayo to make an immediate impact on the New England defense when he returns to game action.
"I think he means a lot to our team," Belichick said Friday. "He's really the guy that the team probably revolves around more than any other player. Not that there aren't other players that are instrumental in that, but I think he touches pretty much everybody. Not just the defensive players, but all of the guys."
New England finished last season 12-4 and lost to the Denver Broncos in the AFC Championship Game.
- Paul Palladino