Mercilus (biceps) was designated to return from injured reserve Thursday, Wes Hodkiewicz of the Packers' official site reports.
Mercilus was initially expected to be out for the remainder of the season after he sustained a biceps injury in mid-November, but he'll rejoin the Packers for practice ahead of the playoffs. Whether he's available for the divisional round remains to be seen, but his return to the practice field is certainly encouraging.