HOUSTON -- Texans coach Gary Kubiak collapsed as he was leaving the field at halftime of Houston's Sunday night game against the Indianapolis Colts.

Kubiak was taken to a local hospital in an ambulance with his family and was conscious, according to the Texans. The team said Kubiak did not have a heart attack and was in stable condition.

Texans coach Gary Kubiak collapsed on the Reliant Stadium turf at halftime on Sunday night. AP Photo/David J. Phillip

"He had an episode, he was light-headed and dizzy," Houston general manager Rick Smith told NBC during a postgame interview. "He was evaluated by a number of specialists ... he is awake and coherent.

"… Hopefully, Gary will be back with us tomorrow."

Kubiak remained hospitalized Monday morning and doctors were conducting more tests to determine what caused him to collapse, a source told ESPN NFL Insider Adam Schefter. They still have not made a final determination. They believe dehydration could be a part of it, but they also are testing for more significant reasons, the source said.

The 52-year-old Kubiak fell to his knees and grimaced when he collapsed, but he never lost consciousness.

"It was really weird," Texans quarterback Case Keenum said. "Someone came in [to the locker room] and started yelling for a trainer. They said that he had passed out and we were all very worried."