Gillislee is a five-year veteran who spent last season with New England. He carried the ball 104 times for the Patriots, gaining 383 yards and scoring five touchdowns. He also caught one pass for 15 yards.
His most productive season came in 2016 with Buffalo, when he rushed for 577 yards and eight TDs to go with 50 yards and one TD receiving.
The Saints open the regular season at home Sunday against Tampa Bay.