West Virginia football coach Bill Stewart has resigned and a university spokesman said coach-in-waiting Dana Holgorsen will take over.

Athletics spokesman Mike Fragale said athletic director Oliver Luck will discuss Stewart's resignation later Friday night and introduce Holgorsen, who was hired as offensive coordinator and eventual successor in December.

In a statement announcing the resignation, Luck didn't give specify reasons and said the university hasn't substantiated allegations of wrongdoing against Stewart.

"He respects the Mountaineer program and the student-athletes he coaches too much to let any conflict and any perception of disorder continue to be a distraction to the staff, team and fans," Luck said. "We both agree that the program's energy and focus should be on the upcoming season."

West Virginia had prepared for possible friction between Holgorsen and Stewart. Holgorsen's contract included a clause that gave him a raise if he became head coach before or during this season.

Luck had said he hired Holgorsen because he believed the Mountaineers couldn't win a national championship under Stewart's leadership. Stewart went 28-12 in three seasons but failed to earn a Bowl Championship Series berth.

Under the transition arrangement, Stewart was supposed take an undetermined administrative position after the 2011 season.

"As you can imagine, this decision did not come easily for either of us," Luck said. "Bill sends this message to all Mountaineers, 'As I said on the day I was appointed head coach, what is best for WVU is my first priority. Today, I am doing what I believe to be in the best interest of the Mountaineer Nation."'

Luck said he modeled the transition to ones conducted when Bret Bielema took over at Wisconsin and Chip Kelly assumed control at Oregon. Luck said he had no doubt it would be handled professionally.

But things started to change after police escorted an intoxicated Holgorsen from the Mardi Gras Casino in Cross Lanes on May 18. No charges were filed. Holgorsen issued a statement saying he had learned a "valuable lesson."

And earlier this week a former Pittsburgh Post-Gazette reporter said Stewart called him shortly after Holgorsen's hiring and asked him to "dig up" some dirt on the new hire.

The former reporter, Colin Dunlap, told KDKA-FM on Monday night that Stewart also called at least one other reporter on Holgorsen. Dunlap said he discussed it with the other reporter, who he didn't name.

Dunlap recalled Stewart saying, "'You need to get it out on this guy.' And I said, 'hey man, I'm not like a part of some witch hunt."'

Luck said Tuesday he wouldn't comment on personnel issues until he had gathered all the facts but reiterated his high expectations of his coaches and staff.

Stewart had been under constant scrutiny since he was named interim coach after Rich Rodriguez's sudden departure for Michigan after the 2007 regular season ended. Stewart led the Mountaineers to a win in the Fiesta Bowl over Oklahoma and was named head coach in the early morning hours after the game.

Stewart, who turns 59 on Saturday, never received annual contract extensions given to Rodriguez by former athletic director Ed Pastilong, who retired last year and was replaced by Luck.

Luck had said part of the reason for the coaching transition was season-ticket sales had declined under Stewart's regime. West Virginia sold out just one home game in 2010 and there were almost 12,000 empty seats for the regular-season finale against Rutgers.

WVU President James P. Clements thanked Stewart, who joined the staff of Don Nehlen as an assistant in 2000, for his long service to the university.

"Like every Mountaineer, I look forward to a great season, and know our athletic department and our student-athletes will work extremely hard to make us proud," Clements said.