Martin, who is set to make just more than $1.1 million this season, will be under contract through the 2022 season.
Martin was drafted in the second round in 2016 and played 30 games in his first two seasons with the Texans. The extension will keep Martin in Houston while the Texans try to build continuity on a line that allowed an NFL-high 62 sacks last season.
He'll work with new left tackle Laremy Tunsil, who was traded from Miami on Aug. 31, as the team tries to better protect Watson after the revamped unit allowed six sacks in a season-opening loss to New Orleans on Monday.
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