49ers place Dorsey on IR; claim Ray-Ray Armstrong off waivers

The San Francisco 49ers placed defensive tackle Glenn Dorsey on injured reserve with a torn ACL, and claimed linebacker Ray-Ray Armstrong off waivers, the team announced.

Dorsey suffered the injury during Sunday's game against the Seattle Seahawks, appearing to make minimal contact against the opposition's line. The veteran lineman recorded 18 tackles in 10 games.

It's likely Arik Armstead will take Dorsey's place in the starting lineup.

Armstrong was waived by the Oakland Raiders on Tuesday, after amassing 21 tackles, one sack, and a pass deflection in 10 games.

The 26-year-old drew scrutiny after being investigated for taunting a police dog prior to a Nov. 8 game against the Pittsburgh Steelers. Armstrong was cleared of all charges when it was found that he wasn't acting maliciously.