Houston had its highlight on Thanksgiving putting the final nail on Matt Patricia's coffin. The Texans are a bad team, two levels lower than the Colts. 
Indy has a top-10 defense. Deshaun Watson is playing at an elite level, but he doesn't have a reliable ground game even if David Johnson returns and now he has a thin wide receiving group with Will Fuller suspended, Kenny Stills gone and Randall Cobb injured. 
The Colts have gotten healthier on defense. They are effective and probing rather than flashy on offense. But they have more than enough manpower to handle a Houston defense that ranks 31st in run defense and 30th in total yards. The Texans also are second-to-last in takeaways.