Dolphins sign two running backs to replace Mattison. What to know
In the wake of losing Alexander Mattison to a season-ending neck injury, the Dolphins moved quickly to add running back depth Monday, signing veterans Aaron Shampklin and Mike Boone.
To make room on the roster, Miami released undrafted rookie receiver Monaray Baldwin and placed Mattison on injured reserve.
Boone, 29, has the more experience of the two new backs; he has averaged 5.0 yards on 117 career carries over 72 games. He has played for Minnesota, Denver, Houston and Carolina over an eight-year career.
Last season, Boone had 13 carries for 59 yards (3.9 per carry) in six games for Carolina. His only two starts came as a member of the Vikings in 2019.
Shampklin, 25, has played only 28 NFL snaps on offense (in three games for Pittsburgh last season) and has six NFL carries, for 17 yards.
Shampklin — who was contacted by the Dolphins immediately after Mattison’s injury on Sunday — was among several backs who worked out for the Dolphins on Monday, a group that also included NFL veteran Jamaal Williams.
Neither Shampklin (5-10 and 195 pounds) nor Boone (5-10, 206) necessarily have the size or girth to replace the 5-11, 220-pound Mattison, who was considered Miami’s best shor- yardage back before an injury during Sunday’s game resulted in surgery that will sideline him for the season.
Boone joined the Vikings as an undrafted free agent out of Cincinnati in 2018.
Shampklin signed with Dallas as an undrafted free agent out of Harvard in 2022. In addition to a stint with the USFL’s Houston Gamblers, he has spent time on the practice squads of the Cowboys, Colts, Chargers and Steelers.
The Steelers elevated him to the active roster for a Week 4 game last season. He was released three weeks later and re-signed to the practice squad. The Steelers released him on May 12, and he previously had workouts with the Bears and Jets in recent months.
Shampklin and Boone join De’Von Achane, Jaylen Wright and Ollie Gordon II as running backs on Miami’s roster.
Shampklin’s special teams ability appealed to Miami, among other attributes.
This story was originally published August 11, 2025 at 3:18 PM.
