Dolphins running back Mark Walton has been suspended four games for violating the NFL’s substance abuse policy, the league announced this week. According to reports, the suspension comes after numerous infractions.

“We have been in communication with the NFL regarding Mark’s suspension,” Dolphins coach Brian Flores said in a team statement. “The conduct of our players is very important and Mark has done everything we have asked of him both on and off the field since signing with the Dolphins. We look forward to having him back at the conclusion of his suspension.”

Walton, who has rushed for 201 yards on 53 carries this season, joined the team in the offseason following his release from the Bengals.

“As most of you know, I was involved in some incidents this offseason that I am now receiving a 4-game suspension for,” Walton said in a statement released Monday by his agent. “I want to apologize to the Miami Dolphins, the fans, my friends and family and I take full responsibility for my actions. I want to thank the Dolphins for giving me this opportunity and will make the most of this chance as a person and player when I return.”