"It's disappointing any time you lose a player for the season, and this is especially true with someone like D'Qwell, who has proven to be an outstanding leader for us both on and off the field," Browns coach Eric Mangini said in a statement released by the team.
Jackson was hurt during the second quarter of Sunday's game. He might have surgery on the shoulder.
Though undersized at 6-foot and 240 pounds, Jackson has been one of Cleveland's best defenders over the past three-plus seasons and was selected as a team captain this year. He led the NFL with 154 tackles in 2008 and was chosen as a Pro Bowl alternate.
A second-round draft pick in 2006, Jackson is eligible for free agency after this season. He had been trying to receive a new contract from the Browns, who might have to play rookies David Veikune and Kaluka Maiava at inside linebacker in their 3-4 scheme.
Jackson has led the Browns in tackles the past two seasons and was second as a rookie in 2006. He had 59 tackles -- 46 solos -- this season and was credited with two broken-up passes and a forced fumble.
Copyright 2009 by The Associated Press