Newly appointed head coach Lincoln Riley is looking forward to coaching the Sooners and is focused on getting to know the players. (2:15)

Bob Stoops' stunning retirement from coaching on Wednesday marks the end of an era at Oklahoma. It also leaves a Texas-sized hole in the Big 12 at a time when the embattled league is struggling to keep pace with the other Power 5 conferences.

Make no mistake: Stoops was the face and bell cow of a league that suddenly feels unrecognizable and in danger of falling further behind its Power 5 brethren in the College Football Playoff pecking order.

In Stoops' 18 seasons as Oklahoma's coach, the Sooners won 10 Big 12 championships. He guided the Sooners to a national championship in his second season in 2000, and his teams played in BCS National Championship games in 2003, '04 and '08, and then the College Football Playoff semifinals in 2015.

During that same period, only two other Big 12 teams -- Nebraska in 2001 and Texas in 2005 and '09 -- played in the BCS National Championship, and the Sooners are the only Big 12 team that has appeared in the three-year-old CFP.

Maybe some fresh blood is just what the Big 12 needs to reinvigorate the league and breathe new life into its best rivalry.

When Texas and Oklahoma play in Dallas on Oct. 14, it will be the first time they've both had new head coaches since 1947. The combined ages of those coaches will be 75 years -- two years younger than Kansas State coach Bill Snyder.

The Sooners replaced Stoops with Lincoln Riley, his 33-year-old offensive coordinator, and the Longhorns hired 42-year-old Tom Herman from Houston in November to replace fired Charlie Strong.

When Stoops was hired at OU in 1999, Riley was still in high school and three years away from becoming a walk-on quarterback at Texas Tech. Herman was a graduate assistant at Texas when Stoops took over the Sooners.

"At the time, they were struggling, and he changed that in a hurry," Herman said in a statement on Wednesday.

Now it's up to the wunderkind coaches whose credentials are as impeccable as they are brief to keep the Big 12 above water. Teams like TCU, Oklahoma State and Baylor have had periods of great success, but for the league to truly flourish, the Sooners and Longhorns need to be national powers. And for that to happen, Herman and Riley need to live up to their lofty reputations.

Certainly, there are legitimate questions about whether Riley and Herman are ready to lead two of the sport's traditional powers. Herman, who earned his reputation as an offensive mastermind while working under Ohio State's Urban Meyer, has two years' experience as a head coach, guiding Houston to 22 wins the previous two seasons. He was the sport's hottest name, and his hiring at Texas seemed like a no-brainer.

Riley is even younger and more unproven. He has been in coaching for only 11 seasons -- and never even worked in the high school ranks. He directed the Sooners' offense the past two seasons, after spending the previous five seasons at East Carolina. His lack of experience makes replacing a coach as proven and successful as Stoops even more monumental.

"You're never ready," said Washington State coach Mike Leach, who hired Riley as a student assistant in 2003. "It's kind of like getting married. You kind of learn a lot along the way and adjust as you go."

Before we write off the Big 12 again, however, remember what happened in the ACC not too long ago.

When Bobby Bowden's dynasty at Florida State fizzled out, and Miami's remarkable run of success ended because of NCAA probation and bad coaching hires, we wondered whether the ACC would ever be relevant again. But then Florida State hired Jimbo Fisher, a first-time head coach, and Clemson promoted Dabo Swinney, who had been a coordinator for all of one season, causing many of us to assume he was in way over his head.

Of course, Fisher guided the Seminoles to a national championship in 2013, and the Tigers won their first national title in 35 years under Swinney this past season. Both Clemson and Florida State will probably start this coming season ranked in the top five.

And if that's not enough evidence to prove what a pair of coaches can do for a league, remember what the Big Ten looked like before Ohio State hired Meyer in 2012 and Michigan lured Jim Harbaugh back to his alma mater three years later. Without Penn State's Joe Paterno, Wisconsin's Barry Alvarez and Ohio State's Jim Tressel stalking the sideline, the Big Ten had become a New Year's Day laughingstock. But in short order, Meyer and Harbaugh made their teams, The Game and the Big Ten relevant again.

Hopefully, Herman and Riley will have a similar effect, and there will once again be more at stake than bragging rights in the Red River Rivalry. If not, we'll still be talking about how the Big 12 is on life support.