Rhodes spent 10 seasons in the NFL, with one of his best performances coming in Super Bowl 41. He rushed for a game-high 113 yards with a touchdown as the Indianapolis Colts capped the 2006 season with a 29-17 win over Chicago.
Rhodes amassed 3,286 rushing yards on 814 carries with 26 touchdowns over his career with Indianapolis, Oakland and Buffalo. In 2001, Rhodes set an NFL record for rushing yards by an undrafted rookie running back with 1,104.
"Dominic will bring veteran competition to the position," said Alouettes general manager Jim Popp. "We love his attitude, he is playing for the love of the game."
Rhodes played the last two seasons for the Virginia Destroyers of the United Football League. The native of Waco, Texas was named the UFL's offensive player of the year in 2011 and he helped guide the Destroyers to a championship that year.
The Alouettes also signed cornerback Jordan Mabin, who rejoins the team after spending two regular-season games last year on the practice roster.
Following his departure from Montreal, he joined the Baltimore Ravens' and Cleveland Browns' practice squads.
"We welcome Jordan back. He is definitely going to be in competition for a job. A very well-rounded player," Popp said.