But really it could mean anything.

They are staying quiet because they are working out the details with the Big XII and don't want to let any details slip or tip their hand.

Or

They are staying quiet because they want to stay with the PAC and are work behind the scenes with the league to add SDSU, UNLV and BSU to the league.

Or even

UofA is waiting on a joint statement with ASU, but ASU started their Fourth of July holiday already and we're too drunk to work with by the time USC and UCLA made it official on Thursday.