Martin, who was born in Jamaica and raised in Canada, played in three games for Miami last season, making one tackle. He was drafted in the fourth round by San Diego in 2009 and played four seasons with the Chargers, making 78 tackles in 48 games. He also had three sacks.
In other news Thursday morning, the Lions have a third player in for a visit -- defensive end/linebacker Darryl Tapp -- along with safety James Ihedigbo and fullback Henry Hynoski. Tapp played in 11 games for Washington last season, making nine tackles and one sack.
He was drafted in the second round by Seattle in 2006 and spent four seasons there before going to Philadelphia for three years.