49ers DT Dorsey suffers torn ACL in knee, surgery pending

San Francisco 49ers defensive tackle Glenn Dorsey's season is over after he suffered a torn ACL in his right knee in Sunday's loss at Seattle.

An MRI exam on Monday revealed the severity of the injury to Dorsey, who may have also sustained a torn meniscus in the knee, a source told the San Jose Mercury News. The 49ers announced that Dorsey's surgery is pending. 

The 6-foot-1, 297-pounder was injured on the Seahawks' first offensive play from scrimmage and the San Francisco was powerless to stop the run without him, allowing 209 rushing yards to Thomas Rawls. Rookie Arik Armstead replaced Dorsey and registered six tackles.

“Glenn can handle both gaps, so you can put emphasis somewhere else because you trust him to be there," San Francisco safety Eric Reid said. "Glenn is a big body, and when he’s not there it’s kind of hard to fill.”

Dorsey started all 10 games, registering 18 tackes in his third season with the 49ers. The fifth overall pick in the 2008 draft, Dorsey spent his first five seasons with the Kansas City Chiefs.