Kubiak hunched over and dropped to his knees at the 24 yard line and was immediately surrounded by medical personnel. He was lifted off the field on a stretcher, taken off on a gurney and transported to the hospital in an ambulance.
The Texans didn't say what was wrong with Kubiak, but did say he didn't have a heart attack. The team said the 52-year-old coach, a former NFL quarterback who calls the team's plays, was conscious and was with his family as he was taken to the hospital.
"He had an episode; he was light-headed and dizzy," Houston general manager Rick Smith said. "He was evaluated by a number of specialists ... he is awake and coherent."
Defensive coordinator Wade Phillips took over as coach. Up 21-3 when Kubiak collapsed, the somber Texans struggled in the second half, falling 27-24 for their sixth straight loss after opening the season 2-0 with Super Bowl hopes.
"We have to assess ... obviously, there's a lot of info," Smith said. "Hopefully, Gary will be back with us tomorrow."
Kubiak's collapse came a day after Denver Broncos coach John Fox was hospitalized in North Carolina as he awaits aortic value replacement surgery. The 58-year-old Fox will have surgery in a few days and will miss several weeks while recuperating.
Kubiak has long been known as a top offensive coach, mentoring quarterbacks in Denver under Mike Shanahan and now Matt Schaub - and Case Keenum - in Houston. Kubiak has had no known public health problems.