Armstead left the field and walked to the locker room shortly before halftime with the Dolphins up 30-0 and did not return for the beginning of the third quarter. Brandon Shell entered the game in his stead.
Dolphins coach Mike McDaniel said after the game that the team will know more about Armstead's injury on Monday. He added that the injury was not one that Armstead could have returned to the game with, regardless of the score.
Armstead, a team captain, has started all but one game this season, playing through a toe injury that he suffered in Week 1. He missed the Dolphins' game against the Minnesota Vikings in Week 6 after seeing a specialist about the injury.
Armstead was Miami's marquee free agent signing this offseason and ESPN's top-ranked free agent in last year's cycle. The 31-year-old signed a five-year, $75 million contract in March after spending the first nine seasons of his career with the New Orleans Saints.