The move is designed ensure Cassel will not be an unrestricted free agent in March, when he could shop his services to the team of his choice.

Cassel had a career year after star signal-caller Tom Brady suffered a season-ending knee injury last September.

The ESPN report added the Patriots would have about $29 million in salary cap space tied up in two quarterbacks, with Brady earning almost $15 million and Cassel guaranteed over $14 million.

The league's salary cap jumps to $123 million per team, which gives the Patriots $94 million to manage the rest of their roster.

"The fact is, nobody knows where I'm going to be next year … . We're going to have to wait and see," Cassel told The Boston Globe in December.

In his fourth NFL season in 2008, the former Southern California quarterback passed for 3,693 yards and 21 touchdowns.