Patriots extend Tom Brady

Tom Brady has agreed to a three-year, $27 million contract extension with the Patriots, a deal that will keep him with New England through the 2017 season, a league source confirmed to ESPNBoston.com's Mike Reiss.

The extension includes a $3 million signing bonus along with annual salaries of $7 million in 2015, $8 million in 2016 and $9 million in 2017, when Brady will turn 40, according to the source.

Brady's relatively modest deal frees up $15 million worth of salary-cap space for the Patriots in the 2013 and 2014 seasons, a league source told ESPN.

While Tom Brady's contract extension lowers his average base salary and creates significant salary-cap space for the New England Patriots to surround him with a team capable of challenging for a Super Bowl, the quarterback also nearly doubled the guaranteed money owed him over the next five seasons, according to a league source who has reviewed the documents.

Until the agreement was revealed yesterday, Brady was under contract to the Patriots for two seasons with a contract containing $30 million in guarantees. Now he's under contract for five seasons with $57 million guaranteed for injury.