Sakamoto criticized Armstead's play during Sunday's 20-14 win over the Denver Broncos, specifically calling him out for his pass-rushing abilities:
Ryan Sakamoto @BEASTwriter_
FInally we are seeing more of Ronald Blair instead of AA on 3rd downs. Safe to say team is not sold on AA as pass-rusher, something that has been evident since day one. A 1st-round pick with high ceiling, who Darnell Dockett believed had Calais Campbell potential. #BEASTwriter
The defensive end responded by calling him a "little man" and an "amateur fan boy" among other things.
The 25-year-old is in his fourth year with San Francisco after being selected with a first-round pick in 2015. He has started all 13 games this season but has only come through with three sacks to bring his career total to nine.