The veteran linebacker was released Tuesday after four seasons in New York, a move earlier reported by NFL.com's Albert Breer and later confirmed by the team. Boley appeared in every game for the Giants in 2012, starting 11 games and finishing fourth on the team with 84 tackles.
The Giants signed Boley to a five-year, $25 million deal in 2009, but he has been a player in decline. According to ProFootballFocus, Boley allowed 550 yards in coverage this season, fifth-most of all 4-3 outside linebackers.
"Michael came in and learned our defense quickly and he added speed, coupled with big play ability, to our defensive unit," Giants general manager Jerry Reese said, according to the team's official site. "He also played an important role in helping us win Super Bowl XLVI. I wish him well as he moves forward in his career."
Boley, 30, led the Giants with 10 tackles in their second Super Bowl win over the New England Patriots. He saw his playing time cut during the second half of the 2012 season due in part to a lingering hamstring injury.
Giants coach Tom Coughlin said in a statement Tuesday that the team "recognized his special skills were in coverage." As his skills in that department faded, so too did the Giants' interest in keeping him in their building.