 Mercilus finished the 2014 season with 50 combined tackles (31 solo) and five sacks in 15 games and 13 starts.On May 4, 2015, the Texans signed Mercilus to a four-year, $26 million contract extension with $10.68 million guaranteed and a signing bonus of $5.25 million.He entered training camp slated as a starting outside linebacker, but saw some minor competition from John Simon after he impressed coaches while filling in for Jadeveon Clowney during camp.