Seahawks running back Chris Carson’s 2021 neck injury will bring an end to his NFL career.

Carson has chosen to retire because of the injury, NFL Network’s Ian Rapoport reported on Tuesday, following a failed physical. The Seahawks reportedly plan to release him with a failed physical designation, allowing him to receive injury protection benefits totaling “several million dollars,” according to Rapoport.

Carson will end his career with 3,502 yards and 24 touchdowns, leaving the Seahawks with a backfield of Rashaad Penny and rookie second-round pick Kenneth Walker III.

Drafting Walker, a Michigan State product, seemed to underscore concerns about whether Carson would make it back onto the field. Seattle was the second team to take a running back in the draft, following the Jets, who took Iowa State’s Breece Hall 36th overall.

In June, Carson had expressed optimism about his ability to return to the field.

“My mindset is to never give up,” he told Heavy.com. “So I’m staying positive like I said, and continue to fight and get back onto the field.”

The Oklahoma State product made a name for himself as a hard-nosed running back who could pick up yardage after contact. In that sense, he felt like a natural heir to Marshawn Lynch in Seattle’s backfield, and he went on to rush for more than 1,100 yards in his first two full seasons.

Carson played four games last year before the injury ended his season.