The Seahawks placed linebacker Jordyn Brooks on injured reserve Tuesday, an expected move two days after he suffered an ACL injury in Seattle's Week 17 win over the Jets.
Brooks, who had a team-high 161 tackles through 16 games, and who was named a Pro-Bowl alternate, will need surgery, Seahawks coach Pete Carroll said.
Filling Brooks' spot on the 53-man roster is tight end Tyler Mabry, who was elevated off the practice squad last weekend to add depth at the position with Will Dissly going on injured reserve last week.
In his first game action of the season, Mabry, a former undrafted free agent who has spent most of the past three seasons on Seattle's practice squad, scored a touchdown on his first career catch, a 7-yard score that gave the Seahawks a 17-3 second-quarter lead.
The Seahawks also signed two players to their practice squad, cornerback Chris Steele and receiver Connor Wedington. Steele, an undrafted rookie out of USC, signed with Pittsburgh after the draft, and also spent time on Miami's practice squad earlier this season.
Wedington, who signed with the Seahawks as an undrafted free agent out of Stanford last year, and has since spent time on the practice squad with the 49ers, Texans and 49ers again. Wedington is from Tacoma and attended Sumner High School.