The Bills have found a pass rusher to team with the free-agent pickup Mario Williams, signing DE Mark Anderson. The contract is a four-year deal, according to Anderson's agent, though financial terms have not been announced.

Anderson was an impact player for the AFC champion Patriots in 2011, registering 10 sacks during the regular season and 2½ during the playoffs. He played in all 16 games a year ago for New England, though he just started one.

A former fifth-round pick of the Bears, Anderson found his greatest success early in his career. He had 12 sacks as a rookie in 2006 and five the next season, but then registered only 8½ sacks total over his next three seasons.

It is expected he will line up across from Williams in Buffalo, with Kyle Williams and Marcell Dareus manning the middle of the team's defensive line. Last week, the Bills signed Mario Williams to a six-year, $100 million contract.