He was timed at 4.36 seconds in the 40-yard draft at the NFL Scouting Combine, and he proved he could make an impact as a rookie. Rainey averaged 26.5 yards per kickoff return for the Steelers, and carried the ball 26 times for 102 yards and two touchdowns as a third-down back.
He also made 14 receptions for 60 yards and returned three punts for 16 yards.
But Pagano was non-committal about Rainey's role as Indianapolis (7-3) prepares for Sunday's game at Arizona (6-4). He said the running back has shown "he's more than capable" in the return game but isn't ready to commit a roster spot to Rainey beyond this week.
"Time will tell," Pagano said.
Rainey said he was close to signing with the Canadian Football League but was told he'd have to make a two-year commitment. So he trusted his agent and waited for another shot in the NFL.
In the interim, he worked out regularly and watched pro football on television until he couldn't take it anymore.
He said he's been humbled by his mistakes and is ready to take whatever role the Colts are willing to give him.
"It's just the same expectations from anybody," Rainey said. "Just come in here, go to work, do your job. The past is the past, leave it there and just move on."