Miami Dolphins running back Alexander Mattison underwent season-ending neck surgery Sunday in Chicago, sources told ESPN's Adam Schefter on Monday.
Mattison suffered the injury after he was tackled on a 21-yard pass play in Sunday's preseason game against the Chicago Bears and was taken by ambulance to a local hospital, where the surgery took place, the sources told Schefter.
He is expected to make a full recovery, sources told ESPN's Jeremy Fowler.
The Dolphins officially placed Mattison on season-ending injured reserve Monday evening.
The Dolphins signed Mattison to a one-year contract this offseason. Many expected him to take over a short-yardage role that the team had lacked in previous seasons.
But he was one of the standout players of training camp, showcasing not just the ability to move the chains in short-yardage situations, but break big runs, as well.
Mattison said the Dolphins didn't pigeonhole him into any specific role and allowed his play to dictate his snaps.
"Seeing as every run that he's had in camp, you can hear me yelling, 'Wait, this isn't short-yardage,'" Dolphins coach Mike McDaniel said. "I think 'Mad Dog' [Mattison] himself is a great example of 'No, here we allow your play to tell us who you are and how you adjust to coaching and how willing you are to invest in your game and your team.'"
With Mattison sidelined, the Dolphins signed veteran running backs Aaron Shampklin and Mike Boone.
Shampklin and Boone will compete with rookie Ollie Gordon II for snaps behind starter De'Von Achane and second-year back Jaylen Wright.
Mattison, 27, appeared in 14 games and made seven starts for the Las Vegas Raiders in 2024. He spent his first five seasons with the Minnesota Vikings and has rushed for 2,790 yards and 15 touchdowns in his career. He also has caught 136 passes for 1,012 yards with seven touchdown receptions.
ESPN's Marcel Louis-Jacques contributed to this report.
