The Phinsider
The Miami Dolphins signed free agent running back Alexander Mattison in the offseason in hopes of adding a power option to their running back corps. In the first preseason game of 2025, Mattison fell awkwardly during a tackle and, despite walking off the field under his own power and head coach Mike McDaniel downplaying the injury in his post-game comments, the running back is now out for the season after having neck surgery Sunday night. The Dolphins scrambled on Monday to workout several free agent runners.
Following the workouts, Miami has agreed to a contract with running back Aaron Shampklin, according to a report from NFL Network’s Mike Garafolo. A 2022 undrafted free agent out of Harvard, Shampklin originally signed with the Dallas Cowboys, but was placed on injured reserve and released as the season started. He signed late in the 2022 season to the Indianapolis Colts’ practice squad, but made no appearances.
He played in 2023 with the Houston Gamblers of the USFL before a brief training camp stint with the Los Angeles Chargers. After missing the season, he signed with the Pittsburgh Steelers for 2024, bouncing between the practice squad and active roster. He was released in May and had tryouts with the Chicago Bears and New York Jets prior to joining the Dolphins.
He appeared in three games with the Steelers, rushing six times for 17 yards.
Shampklin has two preseason games to try to make an impression on the Dolphins’ coaching staff prior to final roster cuts. Miami visits the Detroit Lions this weekend before hosting the Jacksonville Jaguars in Preseason Week 3. Teams must drop from the 90-man preseason roster limit to the regular season’s 53-man limit by 4 p.m. Eastern on August 26.
