The Miami Dolphins announced today that they have signed edge Amari Gainer to the practice squad and released defensive lineman Keith Cooper Jr. from the practice squad.
Cooper Jr., who joined the Dolphins on Jan. 9, 2026, spent the first three weeks of the season on Miami's active roster before being signed to the practice squad. He has appeared in four career games with Cleveland (2025) and Miami (2026), recording one tackle. Cooper Jr. entered the NFL as an undrafted college free agent with Detroit in 2025 and spent time on the practice squad with the Lions and the Browns. He finished his collegiate career at Houston (2024), where he started 12 games and recorded 46 tackles (25 solo), 3.5 sacks, 8.5 tackles for loss, two passes defensed and one fumble recovery. He transferred to Houston from Tulane following the 2023 season after appearing in 39 career games with 15 starts and recording 73 tackles (37 solo), 10.5 sacks, 16 tackles for loss, five passes defensed and one forced fumble in three seasons (2021-23) with the Green Wave.
Gainer first joined the team's practice squad on Sept. 1, 2026. He has appeared in 17 career games in one season with Las Vegas (2024), recording five special teams tackles. He spent time on the practice squad with the Raiders and the Patriots in 2025. Gainer finished his collegiate career at North Carolina (2023), after five seasons at Florida State (2018-22). He appeared in 58 career games with 18 starts throughout his collegiate career and recorded 237 tackles (115 solo), 8.5 sacks, 25.0 tackles for loss, four passes defensed, six forced fumbles and three fumble recoveries.
