This means the Patriots will have to sign him to at least a one-year contract worth the average of the five highest paid quarterbacks in the NFL right now.
The average appears to be between $14.4 million, which is almost $200,000 less than that of Tom Brady's 2009 salary cap figure.
By signing Cassel, the Patriots will have somewhat of a fallback if Brady is not ready to go at the start of the 2009 season.
However, if Brady is 100 percent healthy and able to play, it will make Cassel one of the highest paid backup quarterbacks in NFL history.
On the other hand, the Patriots may franchise Matt Cassel in order to get significant compensation by trading him to another team, or they may work out a short-term deal in order to keep him around until Brady is 100 percent healthy.
Matt Cassel played in all 16 games for the Patriots, throwing for nearly 3700 yards, 21 TDs and leading them to and 11-5 record in the regular season.