John Fox has said that he is "disappointed" that he will be away from the Denver Broncos for several weeks.
The AFC West side's head coach will undergo an aortic valve replacement next week after being hospitalised during a round of golf in the team's bye week.
Fox told the team's official website: "I sincerely appreciate all of the support from friends, Denver Broncos fans and so many around the league today.
"Although I am disappointed I must take some time away from the team to attend to this pre-existing health condition, I understand that it's the right thing to do.
"I have great confidence in our coaches and players, who are fully committed to our goals. I look forward to returning to coaching as soon as possible."
The Broncos are currently second in their division.