The deal is worth $1.9 million, a source told Rapoport, with a chance to make up to $2.5 million.
Decker joins a receiver depth chart that is dealing with injuries and a looming suspension to Julian Edelman. Kenny Britt (hamstring) and Malcolm Mitchell (knee) have been out of practices. Behind Edelman sits Chris Hogan, Phillip Dorsett, Cordarrelle Patterson, Riley McCarron, Braxton Berrios, Devin Lucien and Paul Turner.
Adding Decker provides Tom Brady another veteran presence needed with Edelman set to miss the first four games of the season.
After earning 950-plus yards for four straight seasons from 2012-2015, including three above the 1,000-yard barrier, Decker struggled the past two seasons. After hip and shoulder injuries wiped out his 2016 campaign with the New York Jets, the veteran signed in Tennessee last season. He put up a forgettable campaign with the Titans, earning 54 receptions for 563 yards and one touchdown in 16 games.
If healthy, the 31-year-old Decker could bring the Patriots a reliable route-runner who can function from the slot during Edelman's absence.