MORGANTOWN, W. Va. — On a whiteboard in a conference room, West Virginia defensive coordinator Tony Gibson wrote down a list of returning players who owned at least one career Big 12 start.

When he finished, the list included 16 different defenders.

“Our kids have struggled here,” Gibson said. “A lot of them were playing as freshmen. Three years later, these kids know it’s their time.”

From Major Harris and Pat White to Tavon Austin and Kevin White, West Virginia has cultivated a reputation over the years for winning behind high-flying offenses.

But if the Mountaineers are going to contend in their fourth year in the Big 12, it will be on the backs of a battled-tested and talented defense.

“We’ve put [in] a lot of hard work to get where we are defensively,” coach Dana Holgorsen said. “Right now, we’ve got 16 guys that have been in the Big 12 as long as I’ve been in the Big 12 [at West Virginia] and have started and played.

“Without a doubt, it should be the best [defense] that I've had potentially since I started coaching 20-some years ago.”

The Mountaineers still had some rocky moments defensively last season. But they also showed tremendous improvement over their first two years in the league, ranking eighth nationally in third-down defense and fourth in the Big 12 in points allowed per drive.

They also were especially strong against the nation’s top two scoring teams.

The Mountaineers held Baylor to its lowest point total of the year in a 41-27 win over the Bears. Two weeks later, they almost did the same to TCU, though they couldn’t hold on to a nine-point fourth-quarter lead in a 31-30 loss to the Horned Frogs.

“We turned the corner last year,” Holgorsen said.

The transformation, however, didn’t happen overnight.

In fact, just three years ago, West Virginia finished with the second-worst scoring defense in the country among Power 5 programs, ahead of only Colorado.

In their very first Big 12 meeting with Baylor, the Mountaineers surrendered nine touchdowns alone in a wild 70-63 win over the Bears. Though West Virginia survived, the game foreshadowed tough times ahead for a young defense. But it was also the first brick in the construction of the defense Holgorsen always envisioned having. Freshmen such as Karl Joseph, Nick Kwiatkoski and K.J. Dillon were thrown into the fire that afternoon.

Three years later, they’re the backbone of the Big 12’s most experienced defense.

“We’ve been through the ups and downs,” said Joseph, who is on track to break West Virginia's defensive record for career starts. “We finally know how to win in the Big 12 now.”

The Mountaineers finally have the defensive players they need to win, too.

Joseph is on the short list of Big 12 Defensive Player of the Year candidates and has popped off enough opposing helmets to cement his standing as the hardest hitter in the league. He was second among Big 12 defensive backs in tackles last year and first in forced fumbles.

“He sets the tone for us everywhere, from the weight room to team meetings to practice. He’s the kind of guy everyone dreams about coaching,” Gibson said. “He wants to be great and does whatever it takes. His whole attitude is as good as I’ve ever seen it.”

If Joseph is the Batman of the West Virginia defense, Kwiatkoski is the Robin.

A three-year starter, Kwiatkoski leads all returning Big 12 defenders with 71 solo tackles, and, like Joseph, was a preseason All-Big 12 pick.

“I think he’s as good as there is in the country,” Gibson said. “The year he had was unbelievable. He’s not flashy, but the way he grades out -- people don’t see it, but he makes things happen for the people around him.”

The Mountaineers have the supporting pieces around Joseph and Kwiatkoski, too. Free safety Dravon Askew-Henry was a freshman All-American last year. Dillon has found a home in the “spur,” a hybrid safety and outside linebacker. Junior cornerback Daryl Worley has been a starter since his true freshman season.

And this season, the Mountaineers will welcome back 2013 starter Jared Barber, who missed last season with a torn ACL but is expected to fill a big role again at inside linebacker.

“He’s like our quarterback,” Gibson said of Barber, who donned a headset during games last year, serving as one of Gibson’s de facto assistants.

Getting the right players, though, has been only half of the equation. Underscoring the tumultuousness of the times, the Mountaineers burned through four defensive coordinators in four years during their Big 12 transition.

But after Keith Patterson bolted for Arizona State, Holgorsen promoted Gibson from safeties coach to coordinator last year. And he brought back the 3-3-5 scheme that defined the Mountaineers during the 2000s, and that fueled a West Virginia run that put them a game away from playing for the 2007 national championship.

“We had to get back to what we did here before to get good again,” said Gibson, who was a West Virginia assistant on those defenses before stints at Michigan, Pitt and Arizona. “From day one, the kids bought in.”

Said Holgorsen, “This all starts with Tony. He has a system he believes in, and he knows how to coach it.”

The payoff could come this season.

The Mountaineers will have to force more turnovers in 2015 (they ranked last in turnovers forced last year). And they’ll have to hold up better against the run.

But they also boast a dynamic secondary, a rugged linebacking corps and a veteran defensive line, as well as experienced depth at every level.

“This is the first year I’m coming back with basically the same defense as the year before,” Kwiatkoski said. “Experience is one of the biggest things you can have in college football.”

The Mountaineers have that, and maybe more.

From his whiteboard list, Gibson asked his defenders to vote for the player they thought had been the best offseason leader. Almost every defender on the list got at least one vote. Half a dozen tallied several.

“Our guys have never had confidence before going into a season,” Gibson said. “They have it now.

“That’s why I believe this is a defense that can be great.”