The New England Patriots released tight end Marcellus Rivers after safety Rodney Harrison's roster exemption was lifted. Rivers signed Wednesday when tight end David Thomas was placed on injured reserve. Rivers has played with the New York Giants and Houston Texans in five NFL seasons, most recently with the Texans in 2005. Harrison was suspended for the first four games of the season for violating the league's policy on performance-enhancing substances, reportedly by using human growth hormone. He has played in 168 games for the San Diego Chargers and Patriots.