Denver Broncos head coach John Fox will undergo an aortic heart valve replacement at a Charlotte, N.C area hospital in the next few days, the team announced in a statement late Saturday night.
The statement also said Fox will take a leave of absence from coaching the team for several weeks.
"Our focus at this time is Coach Fox's health and well-being," the statement said. "We extend our thoughts and well-wishes to him for a full and speedy recovery."
Fox was hospitalized early Saturday after a bout of lightheadedness while playing golf in the Charlotte area.
"Coach Fox was advised by doctors months ago that his defective aortic valve would require this procedure following the 2013 season," the team statement noted. "As part of his trip to North Carolina over the bye week, he had a preoperative appointment on Thursday with his doctor, who informed him to seek medical attention immediately if he felt any discomfort.
"On Saturday, Coach Fox began feeling light-headed while golfing with friends. He was taken to a hospital, where testing revealed he needed to have this procedure as soon as possible."
Prior to Saturday's incident, Fox reportedly had hoped to delay any surgery until after this season.
"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," Fox said in a statement also released late Saturday by the team. "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 said they expect to name an interim head coach soon for Fox, 58. It's likely many of his coaching duties and responsibilities will be shared by offensive coordinator Adam Gase and defensive coordinator Jack Del Rio.
In a text message to ESPN senior NFL analyst Chris Mortensen earlier Saturday, Fox said, "I am doing fine. We are just running some tests, will know more in a few hours."
Initial reports indicated Fox might have suffered a heart attack on the golf course, but Broncos executive director of media relations Patrick Smyth tweeted that was not the case.
The Broncos (7-1) are on their bye weekend and play next on Nov. 10 against the San Diego Chargers.
Fox is 28-12 in 2 1/2 seasons with the Broncos, who have won the AFC West title in each of his first two seasons at the helm.