Headline-making, record-setting quarterbacks defined the Big 12 more than any other conference the last two seasons.

Consider the league’s quarterback lineup entering the 2008 season, just two years ago: Sam Bradford, Colt McCoy, Chase Daniel and Graham Harrell. Then add Todd Reesing and Stephen McGee. That constitutes serious star power. Collectively, they produced huge numbers, led their teams to great success and earned invitations to Heisman ceremonies (or the White House, as a consolation prize).

Now, things are decidedly different, which could change national perceptions of the Big 12.

“I think a lot of people nationally see them (Big 12 teams) as being an offensive juggernaut because of what they’ve been able to do with the spread and having so many quarterbacks put up just astronomical numbers,” ESPN analyst Kirk Herbstreit said. “Part of the exciting thing for me in each conference is seeing the turnover and seeing who’s able to pick up the pieces when some of these great players end up leaving.”

The turnover hasn’t been at just one position. The Big 12 had nine first-round picks in the NFL draft, becoming the first conference to produce the first four selections. Of the nine, Bradford was the sole quarterback.

And Mike Leach, who may have done more than anybody else to transform the spread offense from novelty to necessity, won’t be on the sidelines at Texas Tech for the first time in 11 seasons. Depending on your viewpoint, Leach was done in by incredibly poor judgment, a “helicopter parent” or an administration with an agenda. Or all three.

Combined, the losses are beyond significant.

“The landscape has changed as dramatically in the South as I can remember,” said FSN Big 12 studio analyst Pat Jones, a former Oklahoma State coach. “It’s the biggest turnover that I’ve seen.”

The closest thing that the Big 12 has to a Heisman candidate in the making could be Texas A&M’s Jerrod Johnson. No returning quarterback has as many starts (23) or has thrown for as many touchdowns (53).

The biggest immediate worry may be Johnson’s status after spring arthroscopic surgery. While he says he’s 100 percent, he’s shown signs of rust in practice.

Missouri’s Blaine Gabbert, who has seamlessly replaced the charismatic Daniel, ranks as the next-best veteran quarterback.

Elsewhere, question marks abound.

A year ago, Baylor’s Robert Griffin looked like the next great talent in the Big 12, with intelligence, arm strength and remarkable athletic ability. Herbstreit called him one of the “best-kept secrets” in the country. Now his skill set will be scrutinized after knee surgery that limited him to three games in 2009.

Coach Art Briles was encouraged by the way Griffin moved and reacted in something approximating game conditions during the Bears’ first scrimmage this season.

Nebraska, the overwhelming favorite in the North, has returning starter Zac Lee. Cornhusker fans still aren’t sure if that is a good thing after seeing their offense rank 99th nationally, lowest of any team with at least 10 wins. That 10-4 record could easily have been 13-1 with just a little more offense.

Coach Bo Pelini confronted the obvious, saying, “We need the quarterback position to step up.”

The next generation of Big 12 quarterbacks may face challenges beyond experience and injury.

The conference actually had more top-10 defenses than offenses in 2009, a significant turnaround. In 2008, the highest-ranked Big 12 defense (Texas) was 51st nationally.

Herbstreit professes faith in the Big 12’s next generation.

“Maybe it’s not quite the recognition that the Big 12 had at that position the last couple of years,” he said, “but it’s a new wave of very, very talented guys who I think have the ability and the potential to have monster years.”