Dehydration is being considered as at least a partial cause, but doctors are also testing to be sure nothing more significant could be the reason Kubiak fell to his knees in pain while heading to the locker room during the Texans' "Sunday Night Football" game against the
Kubiak never lost consciousness while lying on the ground and being treated by medical staff for several minutes Sunday night and is conscious, alert and in good spirits Monday morning, the source said.
The Texans announced Sunday night that a heart attack had been ruled out.
Defensive coordinator Wade Phillips, the former
"There was a lot of unknown," Phillips said after the game. "Everything was unknown as to what was going on and what happened to Kub. [Offensive coordinator] Rick Dennison obviously called the plays from the press box. We had to adjust as far as the head coach not being there. But it was a shock to everybody."