The Chicago Bears lost two defensive starters for the season during Sunday's 14-3 loss to the San Diego Chargers.
NFL Network's Adam Schefter is reporting that safety Mike Brown suffered a season-ending knee injury, while defensive tackle Dusty Dvoracek will miss the rest of the season with a torn ACL. Both players were put on injured reserve Monday.
Brown's season-ending injury is the third of his four-year NFL career.
Brown has only played 21 regular-season games since 2004. He missed 14 games in 2004 (Achilles), four games in 2005 (calf –- missed last four games of regular season and returned for the playoffs) and 10 games in 2006 (foot).
Brown is the Bears' all-time franchise leader with seven career defensive touchdowns and is second among current Bears with 15 career interceptions. In the season opener at San Diego, the defensive captain had an interception and a fumble recovery. The eight-year NFL veteran was selected to the Pro Bowl following the 2005 season and has appeared in 85 career games with 84 starts -- all with the Bears.
Dvoracek was starting in the place vacated by former Bears DT Tank Johnson, who was released during the off-season after a series of off-field problems derailed his pro football career.
With Brown and Dvoracek out, Smith said safety Danieal Manning and defensive tackle Darwin Walker will start Sunday against Kansas City.
The Associated Press contributed to this report