Indianapolis offensive coordinator Bruce Arians was taken to a hospital in Baltimore on Sunday morning on a gurney after complaining of nausea, headaches, and dizziness.
He is not on the sidelines as the Colts face the Ravens in an AFC wild-card matchup.
ESPN reports that Arians felt he was able enough to go back and call plays in the game, but doctors at the Baltimore hospital refused to let him.
Arians took over for Colts head coach Chuck Pagano after Pagano was diagnosed with leukemia. Arians went 9-3 during that span.
Clyde Christensen, the Colts' quarterback coach, will call the plays against the Ravens. Arians installed the Colts offensive and is considered to be a vital part of the organization, as he proved when he took over for Pagano.