He cites a number of reasons on his twitter feed over the last few days. He mentioned the BYU/Utah matchup as a possiblity as well. He also says UCLA won't play BYU again (they played this season, and they play next season, so the fanbase would be less than thrilled with a 3rd matchup in 12 months a la 2007-08). If his sources are right about Wazzu and UCLA (this all changes if USC goes beats Stanford), Utah could fall to the Vegas. The other possility is that the Vegas bowl decides they want UCLA more and (since UCLA apparently doesn't want a 3rd BYU game in 12 months) BYU ends up in Hawaii (lots of rumors about BYU brass preferring the Hawaii this season anyway). Here are the results of a poll re: Who should the Holiday Bowl take:
https://twitter.com/BonaguraESPN?ref_src=twsrc%5Etfw