Walton was arrested Tuesday morning for aggravated battery of a pregnant woman, according to a police document released to Cameron Wolfe of ESPN.
The woman is five weeks pregnant and Walton is the father. He allegedly pushed the woman into a wall and punched her in the face and head several times.
"We hold our players to a high standard and take these matters very seriously," general manager Chris Grier said in a team statement.
Walton, 22, was suspended for four games in early November for violating the league's substance abuse policy. The ban stemmed from three offseason arrests predating his time with Miami. The Cincinnati Bengals, who drafted Walton in the fourth round in 2018, waived him in April after he was arrested three times in 2019.
The two-year pro started four games and played in seven for the Dolphins this season, accumulating 201 rushing yards and 89 receiving yards.