The Steelers selected Rainey with the fifth pick in the 2012 NFL Draft, but released him over the offseason in the wake of multiple run-ins with the law. The final straw was an incident in which Rainey was arrested for allegedly slapping his girlfriend. The girlfriend has since denied that she was assaulted.
The speedy back, who ran a 4.3 40-yard dash in a tryout with the Chiefs two months ago, rushed for 102 yards and two touchdowns on 26 attempts and caught 14 receptions for 60 yards as a rookie. He also served in a special teams capacity, returning 1,035 yards worth of kick returns.
Starting Colts running back Trent Richardson has struggled since arriving from Cleveland earlier this season in a blockbuster trade. He's averaged just 2.8 yards per carry in Indy and has been routinely outplayed by backup Donald Brown.
While the shifty 5'9 and 180-pound Rainey will fill a different role than that of the 225-pound Richardson, his signing could be a signal of discontent among the Colts brass, despite recent assertions to the contrary.