Walton is on the rookie minicamp roster as a tryout player. The Bengals selected Walton in the fourth round of the 2018 NFL Draft. Cincinnati waived him in April after he was arrested in Miami.
The 22-year-old running back had 34 yards on 14 carries in 14 games last season for the Bengals. Walton wore No. 17 on Friday at the Dolphins' training facility.
Former University of Miami players Malik Rosier, Sean McGuire, Darrell Langham and Kendrick Norton were also at Dolphins rookie camp on Friday.
Robert Ritrovato, Myles Gaskin, Chandler Cox and Patrick Laird are the other running backs listed on the Dolphins' rookie minicamp roster.
Kenyan Drake enters the 2019 season atop the Dolphins' depth chart at running back. The Dolphins also have Kalen Ballage, who the team picked in the fourth round of the 2018 NFL Draft. Veteran Kenneth Farrow will also be competing for carries this off-season. Miami signed Farrow in April out of the AAF.
The Dolphins wrap up rookie minicamp Sunday before beginning OTA off-season workouts Monday.