NORMAN – Count Steve Owens among those stunned by Wednesday’s announcement that University of Oklahoma head football coach Bob Stoops was retiring, effective immediately.

“Like most of us, I am shocked about Bob, but it’s not surprising,” said Owens, who won the 1969 Heisman Trophy at OU.

“He’s been here for 18 years and has had tremendous success,” Owens said. “He’s become such a great friend of mine. I just love the guy. I am happy for Bob. The Sooners have been so fortunate to have had him.

“He feels he has fulfilled his mission here at Oklahoma, so he says he’s going to retire.

President David L. Boren announced at a press conference Wednesday evening that offensive coordinator Lincoln Riley would be Stoops’ successor.

“I think Bob felt like the program was in great shape, had great coaches, some great players and had a great recruiting year, so it was a good time for him to retire.”

Riley, 33, is the youngest head coach in FBS.

Just last month, Riley received a three-year contract extension worth $1.3 million per year, making him one of the highest-paid coordinators in the country.

“I am so impressed with him,” Owens said. “He’s sharp. He is an excellent coach. He’s done a good job in the two years that he’s been here.”

Stoops, 56, was the longest-tenured active coach in major college football, taking the job at Oklahoma a day before Kirk Ferentz started at Iowa.

Stoops felt the time was right.

“I didn’t want to miss the right opportunity to be able to step away and hand this baton off to Lincoln Riley and to help keep this all just going in a great direction,” Stoops said at the press conference.

Stoops was 190-48 — his only college head-coaching job.

Boren and athletic director Joe Castiglione hired stoops in 1999 after serving as defensive coordinator at Florida.

Stoops had a.798 win percentage, and his 190 wins were more than OU legends Barry Switzer (157) and Bud Wilkinson (145).

“When he came here, who would have thought that he would stay for 18 years and have the success to win 190 football games,” Owens said. “Who would have thought it? We should all be thankful that Bob Stoops came into our lives.”

“We will be talking about his era for many years to come,” Boren said.

Boren said Stoops would remain at OU as a special assistant to the athletic director.

“Wow. What a day,” Riley said moments after receiving a No 1 Sooner jersey from Boren and Castiglione. “As a young coach and decide that you want to do this, these are things you just dream about. I feel like I am honestly living a dream right now. It’s just an incredible feeling.”

Riley takes the reins of a program that will again be the favorites to win the Big 12 and a College Football Playoff, with a Heisman Trophy finalist in quarterback Baker Mayfield.

His first game will be at home against UTEP on Sept. 2. His second game will be at Ohio State.

The Sooner program had struggled for more than a decade to replace Switzer. Stoops quickly returned Oklahoma to national prominence, winning a national championship in his second season with a win over Florida State.

His early success that included three straight victories in major bowls and a five-game winning streak against Texas earned him the nickname "Big Game Bob."

While Stoops was not able to bring another national championship to Norman, he did lead Oklahoma to three more BCS championship games and a spot in the College Football Playoff two years ago.

– The Associated Press contributed to this report.