NFL Network first reported the news.
The Patriots acquired Sanu last October from the Atlanta Falcons for a second-round pick, a significant investment that resulted in Sanu playing only nine games for the team.
Still, the move doesn't come as a surprise due to a combination of finances and overall fit in the Patriots' receiving corps.
Sanu was due to earn $6.5 million this season, which is a high figure based on his projected role as a No. 4 option who doesn't contribute on special teams.
Furthermore, because the Patriots are locked in with Julian Edelman and 2019 first-round pick N'Keal Harry as two of their top receivers -- giving them one of the slower top tandems in the NFL -- their ideal third receiver would be someone with speed.
That isn't Sanu's specialty, as he's more of a crafty inside receiver who plays with a physical edge. Free-agent signing Damiere Byrd, a former track star in high school who also competed at South Carolina, is a top candidate to fill that role.
In 2019, Sanu got off to a fast start in New England, catching 10 passes for 81 yards and a touchdown in his second game, before he sprained his ankle returning a punt in his next game. That seemed to slow him down the rest of the season, and he underwent offseason surgery.