The 42-year-old Walton has coached the Lions secondary since 2009. Before that he was the defensive coordinator at the University of Memphis.
The opening of the Rams defensive coordinator spot was up in the air, as last season Gregg Williams was suspended, and the spot was shared by a couple coaches.
Williams is back, but not with the Rams, as he is now an assistant with the Titans.
The Rams were 19th in the league in total defense last season.