Bowens, a special teams captain last season, played in 32 games with seven starts in two seasons with the Jets. A popular player in the locker room, Bowens filled in last year at inside linebacker when David Harris was injured. He had 31 tackles, four sacks, an interception and two forced fumbles.
Bowens, 31, signed as an unrestricted free agent in 2007 after seven seasons with Miami.
Kassell, 29, spent last season on injured reserve with a knee injury after two seasons as a special teams standout for New York. He played in 32 games with two starts for the Jets after signing as an unrestricted free agent in 2006 following four seasons with Tennessee.