(Houston, TX) -- The first round of the Houston Open is teeing off Thursday. Six Americans will get the day started as the first group. Jason Dufner, Kyle Stanley, Russell Henley, Bronson Burgoon, Scott Stallings, and Kelly Kraft begin the tournament. Last year's champion Carlos Ortiz will not be participating in this year's Houston Open. Viktor Hovland will also not be participating after he came away with last week's WWT Championship.