Ravens linebacker Brendon Ayanbadejo (thigh) also is active. Both McClain and Ayanbadejo were listed as questionable on Friday's injury report.
Carr missed seven games during the regular season with thigh and back injuries, although he did see action in the final three games. Brown played on special teams in the regular-season finale against the Cincinnati Bengals and participated in just seven games this season.
The Associated Press contributed to this report.