Kelly was promoted to the Rams' active roster Saturday.
With Darrell Henderson (ankle) on injured reserve, Kelly will serve as the No. 3 running back in Sunday's season finale against the Cardinals. Kelly -- a sixth-round pick by the Rams in the 2018 NFL Draft -- has suited up in seven NFL games, rushing 30 times for 81 yards (2.7 yards per carry) and catching two passes for 27 yards.