 During Week 15 against the Tennessee Titans, Mercilus intercepted a pass thrown by Ryan Tannehill and returned it for 86 yards during a 24–21 victory.In the next game against the Tampa Bay Buccaneers, he sacked Jameis Winston twice during the 23–20 road victory.On December 28, 2019, the Texans signed Mercilus to a four-year, $53.5 million contract extension with $28.5 million guaranteed.