The seven-year-veteran, who's been a starter for the Lions over the last four seasons, has been out all offseason after undergoing toe surgery.
Houston signed a five-year, $25-million contract with the Lions last spring and missed four games because of toe and foot injuries. The 29-year-old had 44 tackles with two interceptions in 12 games last season.
In 99 career games, he has totaled 376 tackles with 13 interceptions.
The cap savings allowed the Lions to sign first-round pick Eric Ebron earlier on Friday.