ESPN's Adam Schefter reported the news via Twitter.
Mayo, still just 25 years old, was the team's first-round draft pick in 2008, when he won NFL Defensive Rookie of the Year honors. He led the team in tackles in his rookie season with 128 and again in 2009, despite missing nearly four full games. He led the entire NFL with 175 tackles in 2010, when he was named to his first Pro Bowl team.
In his second year as a captain for the Patriots, Mayo is third on the team with 68 tackles, and he has interceptions in his last two games, after going without a pick for the first three-plus years of his career.
Mayo's rookie deal went through the 2012 season, but he was grossly underpaid, making somewhere around $600,000 in base salary this season.