I think it's because OSU/BU are in primetime as well. FS1 is taking one to the balls since they don't want to split the marquee match ups at the same time.
The Pac-12 has four games that weekend still showing as TBD, and my guess is that two of them will be on Fox (2:30/7:30):
ASU/UCLA
Oregon/Arizona
Cal/Stanford
USC/Colorado
There was also some provision in the Pac-12 contract that said they needed to have X number of games on Big Fox, and they were coming up short thus far. We've had at least one game on Fox the last six weeks. My guess is that 11/19 will be a Pac-12 double header on Fox (2:30, 7:00 PM) and a 2:30 game on FS1 since you can bury 6-4 KSU and 8-2 OU at 11 AM and you can't with a Pac-12 team.
I bet it goes like this...
11 AM (FS1) OU/KSU
2:30 PM (FS1) Oregon/Arizona
2:30 PM (Fox) ASU/UCLA
7:00 PM (FS1) KU/ISU
7:00 PM (Fox) Stanford/Cal
7:00 PM (ABC) Baylor/OSU
They'll squeeze USC/Colorado onto the P12N somewhere in the middle of all of that mess because they bury 90% of Colorado games on P12N.
So, we were probably screwed because (1) the Pac-12 is short on the Fox quota, (2) they don't want to split OU fans watching the Baylor game out of spite and OSU fans watching OU get trounced by us, and (3) no one in the Pac-12 can be on FS1 before 2:30.
I think they'd probably put us on Big Fox at 2:30 if they could, but I don't think they can at this point.