Ellington rejoins former Cardinals and current Bucs head coach Bruce Arians in Tampa Bay. Arians will return to the sideline after the Buccaneers hired him Jan. 8 to be the team's next head coach.
The club didn't release details of Ellington's contract.
The Cardinals drafted Ellington in the sixth round of the 2013 NFL Draft, Arians' first season with the franchise. The running back and coach reunite after both sat out of the 2018 season. Arians retired after his fifth season with Arizona, and Ellington opted to not sign with a team in free agency.
Ellington played in 65 games with 18 starts for the Cardinals, rushing 413 times for 1,750 yards and 10 touchdowns. He also served as a pass catcher in Arians' offense, catching 145 passes for 1,296 yards and three scores.
Arizona waived Ellington in November of the 2017 season. The Houston Texans claimed him, and he appeared in four games (two starts) with the team.