The Chicago Bears placed long- reserve Monday, officially ending his season.
The veteran suffered a ruptured ACL in his knee in Sunday's 31-20 victory over the San Diego Chargers.
Mannelly has played 215 games in a Bears uniform, the most in franchise history, since being drafted by the club in 1998.
He has suited up for 14 full seasons in Chicago, which ties him for the most years of service in team history with Doug Buffone (1966-79) and hall-of-famer Bill George (1952-65). He had played in 147 consecutive games.
In other Bears news, the team waived defensive end Mario Addison.
Addison appeared in three games for Chicago this season after entering the NFL as an undrafted free agent out of Troy.