I see the spread just clicked down another .5 to 9.5. This is a change from the original 13.5.
GO BOBCATS
The spread has nothing to do with who they think will win - it's all about making money. OU plus 13.5 would have been a real good bet.
The spread at the beginning reflects the result that Las Vegas expects. By the end of the week the spread reflects the result that gamblers expect. Since the bookies want to be assured of a safe profit, they shift the spread to try to attract equal amounts of money on both sides. Apparently the gamblers agreed that OU at 13.5 was a good bet, so money came in on that side. At 10.5 slightly more money was still coming in on the side of OU, apparently, so the spread ticked down a little more.