This move is likely to free up a roster spot for OLB Phillip Hunt, who was signed to a contract on Monday.
Dunbar, 30, originally signed on with the Saints as an undrafted free agent back in 2008. He spent over four years in New Orleans before joining the Rams as an unrestricted free agent back in 2012.
Dunbar was released by the Rams at the start of the season as they trimmed their roster down to 53 players. The Rams did, however, elected to bring him back before releasing him mid-season.
The Saints signed him to a contract towards the end of October.
This season, Dunbar has appeared in three games and recorded 11 tackles for the Saints.