Brooks sustained an ACL injury in their 23-6 win over the New York Jets on Sunday, coach Pete Carroll confirmed on Monday.
"That's a shame," Carroll said on Seattle Sports Radio 710 AM. "What a great, great player and a great teammate."
Carroll didn't go into specifics on Brooks' ACL injury, only calling it "legit." It's unclear how long he will be sidelined, but his season is done regardless of whether Seattle makes the playoffs or not.
Brooks went down in the second quarter on Sunday while trying to tackle Jets tight end C.J. Uzomah. Brooks planted his right leg and fell awkwardly as he spun Uzomah out of bounds. He reached for his knee quickly, clearly in pain, and was carted off from the sidelines before the Seahawks ruled him out for the rest of the game.
Brooks had four tackles against the Jets. He has a team-high 161 total tackles this season, his third with the Seahawks. Only Jaguars linebacker Foye Oluokun and Chiefs linebacker Nick Bolton have more across the league. Brooks had a career-high 184 tackles last season, which set a franchise record and secured his spot as the team's new starting linebacker before the Seahawks released longtime linebacker Bobby Wagner this past offseason.
He has one year left on his initial four-year, $12 million deal with the Seahawks.
Seattle enters its season finale on Sunday still in the hunt for a playoff spot in the NFC. The Seahawks can take the last wild-card spot if they beat the Los Angeles Rams at home and the Detroit Lions beat the Green Bay Packers. If the Packers beat the Lions, however, they will take the playoff spot.