Duke basketball coach Mike Krzyzewski is expected to coach the Blue Devils Wednesday evening, but beyond that, it is unclear just when the Hall-of-Famer will return to the bench.

Several media outlets are reporting (ESPN was the first to break the story) that Krzyzewski will undergo back surgery Friday, forcing him to miss an undisclosed amount of time. Assistant coach Jeff Capel (a former NCAA head coach and Duke standout) will take the helm in his stead.

From ESPN:

Krzyzewski is expected to coach Wednesday against Georgia Tech and then step away for the surgery to remove a fragment of a herniated disk in his lower back. The procedure has an anticipated recovery time of four weeks.
“His back has been bothering him way worse than he’s let on,” a source told ESPN.
Assistant coach Jeff Capel will coach the team while Krzyzewski recovers. Capel’s first game will be Saturday against Boston College.
“Dr. William Richardson, Dr. [Allan] Friedman, and our medical team have worked tirelessly to help manage this issue for several weeks,” Krzyzewski said in a statement. “Together, we have determined that surgery is the best course of action at this time. During my recovery process, the team will be in the capable hands of Coach Capel, Coach [Nate] James and Coach [Jon] Scheyer. As soon as the doctors clear me to do so, I look forward to returning and giving our team 100% of my energy and attention, which is certainly something that they deserve.”

The last time Krzyzewski took an extended leave of absence from the team, it didn’t go well. In 1995, Coach K left coaching to tend to his back, and the Blue Devils finished the season 13-18.