According to Jordan Schultz of Yahoo Sports, Houston "has made it a priority to extend" Mercilus' contract prior to next season.
Mercilus is not set to be an unrestricted free agent until 2020, per Spotrac, but he has a potential out in his contract in 2018.
The Illinois product played just five games last season because of a torn pectoral muscle, though he was durable before the setback and appeared in at least 15 games in each of his first five years in the league.
He is still just 27 years old and has proven himself as a force along the defensive front when healthy. He tallied 12 sacks in 2015 and has at least five every season except for 2017.
The idea of Mercilus, J.J. Watt and Jadeveon Clowney wreaking havoc against AFC South offenses for years to come is surely enticing to Houston's front office, especially as the team looks to bounce back from a 4-12 effort last year.
Signing a healthy Mercilus long term would give the Texans a building block along the defensive line next to the dominant Watt.