Kansas City Chiefs offensive coordinator Charlie Weis underwent surgery Monday to remove an infected gall bladder, his agent confirmed to ESPN.
Weis first experienced pain Friday but chose to coach the Chiefs during their 31-10 win over the San Francisco 49ers on Sunday, according to his agent, Bob LaMonte.
"Charlie is one tough dude," said LaMonte. "He wanted to see his son, Charlie Jr., play football on Friday after [Chiefs] practice. He was in so much pain, he went home, got into bed, took a lot of pain medication and insisted on coaching despite the diagnosis."
Weis and the Chiefs have no other specific comment, but LaMonte said Weis is scheduled be discharged from the hospital Tuesday and will resume his coaching duties in the near future.
Earlier, Chiefs coach Todd Haley had revealed Weis had an undisclosed health issue that was not life threatening.
"As is my policy, I won't talk about anybody's ... health ... that's a family business deal," Haley said Monday. "That being said, there's nothing life-threatening, heart attack-related, any of the couple of things that have been brought to my attention regarding Charlie. I will make that statement just to keep there from being a bunch of hoopla. I won't get into the personal side with any of our associates, employees, coaches, players."
The Chiefs have been one of the NFL's biggest surprises with a 3-0 start, and Sunday's offensive output was their most productive game.
"Charlie joked that maybe he should coach in that much pain every week," said LaMonte.
Weis, the offensive coordinator for New England's Super Bowl teams, was hired by the Chiefs after being fired last year as head coach at Notre Dame.
He underwent knee surgery in the offseason and spent most of training camp moving around on a motorized card and walking with difficulty with a cane and wearing a large knee brace. All he has said about that situation was that part of his knee "fell off" a few weeks before camp opened.
The Chiefs have a bye week after winning their first three games of the season.
Chris Mortensen is ESPN's senior NFL analyst. Information from The Associated Press contributed to this story.