Winnipeg (1-8) signed Levi Brown, who spent last season with the Saskatchewan Roughriders.
Brown was a 2010 seventh-round draft pick of the NFL's Buffalo Bills.
Brown saw action in Buffalo's final regular-season game as a rookie, completing two-of-three passes for 24 yards.
The 26-year-old from Mount Juliet, Tenn., spent the following season on the Bills' practice roster.
He joins Jason Boltus, who signed last month with the Bombers, as well as Max Hall, Justin Goltz and Buck Pierce on Winnipeg's quarterback depth chart.