 Mercilus finished his rookie year with 25 combined tackles (20 solo), six sacks, and a pass deflection in 16 games and four starts.The Texans finished atop the AFC South with a 12–4 record and earned a playoff berth.On January 5, 2013, Mercilus appeared in his first NFL playoff game as the Texans defeated the Cincinnati Bengals 19–13 in the AFC Wildcard Game.