@DinarHawk
The Vegas betting line, odds and point spread.
The current odds in KU's group are:
Florida 1:1
KU 3:1
Syracuse 6:1
If you see the KU odds go shorter, say 2:1 or 1:1, it would certainly indicate that Embiid is coming back and KU chances have improved. The odds are constantly tweaked to make sure money is bet evenly.
Likewise, the point spread for the KU EKU is KU -15, which means that KU is expected to win by 15 points. If too much money is being bet on one side, then Vegas changes the spread so half the money is bet on each side. If a lot more money is wagered on one side, Vegas can either win a lot of money of lose a lot of money depending on the outcome of the game; they don't like that uncertainty. If the money wagered is evenly divided they are guaranteed to make money of the vigorish or "vig" or "juice" which is the fee the casinos (or bookies) charge to take the bet. If the point spread suddenly moves to KU-20, then you know that it is likely that Embiid will be playing.
Google Vegas odds and Vegas point spread and you will find plenty of information on the subject