Police in the Fort Lauderdale suburb of Davie said in a report that officers went to a home at 4:15 a.m. Tuesday, where Walton's girlfriend told them he had pushed her against the wall and punched her several times in the face and head, leaving her with a swollen left eye.
The woman told officers she is five weeks pregnant with the couple's child and had told Walton about the pregnancy on Sunday. Walton, 22, was charged with aggravated battery on a pregnant person, a felony with a 15-year maximum sentence. It was his fourth arrest in less than a year.
Because this is a domestic violence charge, Walton will have to appear before a judge before he can be released and he was not listed on the court's Tuesday afternoon calendar.
His defense attorney, Michael A. Gottlieb, declined comment and his contract representatives, First Round Management, did not immediately return a call seeking comment.
The Dolphins announced Walton's release less than seven hours after his arrest. The second-year player had served two games of a four-game suspension for violating NFL conduct and substance abuse policies following three arrests last offseason in his hometown of Miami.
"We were made aware of a police matter earlier this morning regarding Mark Walton. We hold our players to a high standard and take these matters very seriously. We will have no further comment at this time," General Manager Chris Grier said in a statement.
The Dolphins signed Walton in May, one month after the Cincinnati Bengals released him because of the earlier arrests.
"I think people deserve a second chance," Dolphins coach Brian Flores said then. "I don't want to judge people based on one incident, two incidents."
The Bengals had drafted him in the fourth round of the 2017 draft out of Miami. As a high schooler, Walton starred at Miami powerhouse Booker T. Washington.
A Florida court sentenced Walton in August to six months' probation after pleading no contest to a misdemeanor weapons charge. Other charges, including marijuana possession and reckless driving, were dismissed.
The NFL suspended Walton two weeks ago and he had been eligible to return Dec. 2. The suspension had been expected when the Dolphins signed him. Flores said at the time that Walton "has done everything we have asked of him both on and off the field."
In seven games with the Dolphins this season, Walton rushed 53 times for 201 yards, an average of 3.8 yards per carry. He also had 15 receptions for 89 yards.
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