Even before Colorado became the official 11th member of the Pac-10, Oklahoma athletics director Joe Castiglione felt the pinch of conference realignment.

As reports swirled that Nebraska is just about ready to announce a shift to the Big Ten, Castiglione, who helped put together the Big 12 in early 1990s as the AD at Missouri, said the news isn't good.

"I think it's over with them (Cornhuskers)," a dour Castiglione said in a late-night telephone interview with Dave Sittler of the Tulsa World. "It feels like somebody died. It's that emotional for so many people who put so much into creating the Big 12."

And now that Colorado has beaten Nebraska to the punch, there are now two near-certain holes in the Big 12's lineup.

Whether this means the league will fold and five teams -- Texas, Texas A&M, Texas Tech, Oklahoma and Oklahoma State -- will also head to the Pac-10 remains to be seen.

On Thursday, amid the news of Colorado's move, Sittler posted an item on his blog saying if the Big 12 wants to remain, they need to make a major push to get Arkansas to leave the SEC and also look to add Air Force in the mix. Brigham Young is another possibility for the Big 12 if the league's remaining teams look to keep the league running.

Castiglione acknowledged that BYU and Air Force are two teams the Big 12 might look at if it can convince Texas to help hold the conference together.

Texas, which yields enormous power in the Big 12 because of its revenue-making ability, could lose some of that power in a shift to the Pac-10, one reason Castiglione feels the Longhorns could push to keep the Big 12 intact.

"We worked really hard (with Nebraska) to try and make this work," a subdued Castiglione said, according to the Tulsa World. "But it apparently wasn't enough."