Gary Kubiak collapsed as the team left the field at halftime. (David J. Phillip / AP)

Houston Texans Coach Gary Kubiak, who remains hospitalized today after collapsing Sunday night at halftime, was treated with IV medicine “designed to break up clots consistent” with strokes, ESPN’s Adam Schefter reports.

The Texans said Sunday night that the 52-year-old coach, who sank to his knees and grimaced as he walked off the field during the game against the Indianapolis Colts, had not suffered a heart attack and offered no other information. Schefter cautions that the treatment isn’t a sign that Kubiak suffered a stroke, merely that he was treated with anti-clotting meds immediately after being taken by ambulance to a Houston hospital. He was expected to undergo further tests and will be hospitalized for at least another 24 hours, the Texans said today.

“Our primary concern is of course with Gary’s health and well-being,” General Manager Rick Smith said in a statement released by the team. “There have been so many people throughout the city and across the country that have reached out to express their love and support and we are thankful for everyone’s thoughts and prayers. Gary is alert, coherent and in good spirits. He is continuing to be evaluated and monitored.”

Kubiak was taken immediately by ambulance to a Houston hospital.

“I saw him on the ground and I was asking, ‘What happened?’ ” Wade Phillips, the defensive coordinator who coached the second half in Kubiak’s place, said. “That’s kind of how it was with everybody, with everybody asking, ‘What happened? What happened? What happened?’

“There was a lot of unknown. … It was a shock to everybody.”