The Stampeders signed the former top rookie Thursday. Mallett missed the entire 2012 season with a torn Achilles tendon before being released by the Hamilton Tiger-Cats last May.
Mallett was the CFL's top rookie in 2009 while with the B.C. Lions. He ran for 1,240 yards and six TDs that season while adding 43 catches for 342 yards and two touchdowns.
"Martell demonstrated great ability when he first arrived in the CFL and I know he's looking for a chance to prove that he is healthy and once again able to be a productive player," Calgary coach/GM John Hufnagel said in a statement. "We're hoping he can add depth to both the running back position and our return game and I'm looking forward to seeing him in action at training camp."
Mallett. 27, signed with the NFL's Philadelphia Eagles in 2010 and also spent time with the Cleveland Browns and New York Giants before returning to the CFL with Hamilton.
"I've been working hard this past year and I'm 100 per cent healthy again," said Mallett. "I'm very grateful to the Stampeders for this opportunity and I can't wait to get back on the field."