Jonathan Greenard found the end zone for the first time in his NFL career.
The third-year defensive lineman corralled a Sam Ehlinger pass in the middle of the line of scrimmage, and then raced 39 yards to the right for a touchdown. The Ka'imi Fairbairn extra point staked the Texans to a 17-7 lead with 10:41 remaining in the first half.
The play before, the Texans' Royce Freeman fumbled at the Indianapolis 14-yard line, and Julian Blackmon picked it up and ran to the Colts' 42-yard line.
Earlier in the game, Houston jumped out to a 10-0 advantage with a Davis Mills-to-Brandin Cooks touchdown pass and a Fairbairn field goal after the Colts fumbled a kickoff return.