McClain, a three-year starter, hadn't practiced with the Ravens before this week. He had full practices all week and was listed as probable for Sunday's game against the Pittsburgh Steelers.
There is a possibility McClain could against Pittsburgh because Josh Bynes, who had replaced McClain in the starting lineup, is out with a finger infection.
McClain ranked among the top three tacklers for the Ravens for the past three seasons.
The Ravens cut tight end Billy Bajema to make room for McClain.