49ers' Dorsey diagnosed with torn ACL

San Francisco 49ers defensive tackle Glenn Dorsey suffered a torn ACL, the team confirmed Monday.

Dorsey underwent a MRI on Monday after being carted off the field following a play where he made minimal contact at the line of scrimmage against the Seattle Seahawks on Sunday.

Arik Armstead, a 2015 first-round pick, will likely be inserted into the starting lineup with Dorsey lost for the season.

Dorsey recorded 18 tackles in 10 games.