 Mercilus finished the 2015 season with 52 combined tackles (32 solo), a career-high 12 sacks, and two pass deflections in 16 games and 10 starts.The Texans finished atop the AFC South with a 9–7 record and earned a wildcard berth.On January 9, 2016, Mercilus started his first NFL playoff game and recorded eight combined tackles and sacked Chiefs quarterback Alex Smith thrice during a 30–0 loss to the Kansas City Chiefs in the AFC Wildcard Game.