In addition, the Patriots released OL R.J. Dill from the practice squad.
Mattes, 23, was originally signed by New England as a rookie free agent on May 13 out of North Carolina State before being released on May 23 and re-signed on June 3. He was released again on Aug. 24. The 6-foot-6, 315-pounder, was a four-year starter at both guard and tackle and was named a second-team All-ACC as a senior in 2012.
Reed, 22, was originally signed by the Dallas Cowboys as a rookie free agent out of Southern Methodist on May 5, 2013. The 5-foot-11, 236-pounder was released by Dallas on Aug. 31 before being signed to the Cowboys practice squad on Nov. 18. He was released from the practice squad on Nov. 26. Reed started in 12 of 13 games as a senior in 2012 and led the team with 97 total tackles and earned All-Conference USA second-team recognition.
Dill, 23, was signed to the New England practice squad on Dec. 2, 2013. He originally was signed to the New England practice squad on Sept. 3, 2013, and was released on Sept. 13, 2013. The 6-foot-6, 316-pounder was signed by the Jacksonville Jaguars as a rookie free agent out of Rutgers on April 28, 2013, and was released by the Jaguars on Aug. 30. He started all 13 games at right tackle for Rutgers in 2012 after transferring from Maryland following the 2011 season. Dill was a three-year starter at Maryland.