According to published reports, "Former UCLA chancellor Chuck Young is leading the opposition of adding Colorado and Utah to the league."
The very, VERY, VERY likely scenario is that everything goes off without a hitch and the Buffaloes and Utes join the Pac-10.
However in the unlikely event that there is enough Pac-10 dissention, the question then for Big 12 brass is whether the league would accept the Buffs back into the conference.
I think after how the conference accepted Mizzou back into the mix after their "secret" flirting with another conference, that CU would be gladly welcomed back (if for nothing else than the Denver TV market).
CU has always been the outlier of the conference... a different time zone... the furthest West.. and I even outlined their exit last September here.
But with that said, I think that if the apocalypse happened and they were a team without a conference that the Big 12 would be idiotic not to invite them back. The other option for CU would be the Mountain West conference, which would be a coup for that conference and come back to haunt the Big 12.
So the question for you, the fan, is whether you would want them back. How would you feel if this unlikely scenario played out?