Lemon has played in the CFL, the Arena Football League, and most recently been part of the Pittsburgh Steelers, who he signed with back in January.
In the CFL, he had 66 tackles, 22 sacks and three forced fumbles over his career in the league. Lemon played college football at Akron.
The signing comes just one day after the release of star linebacker Aldon Smith following his Thursday night arrest.