McAllister practiced at the club's suburban headquarters and could be activated for Saturday's divisional round playoff game against the Arizona Cardinals.
Payton confirmed the decision in a text message to The Associated Press. WWL-AM, the radio station that broadcasts Saints games, first reported the move.
The 31-year-old McAllister was waived by the team shortly after last season. He has been working out on his own and rehabbing a knee injury.
He is the Saints' career rushing leader. His 55 total touchdowns and 49 rushing TDs also are club records.