I watched the preseason between the cavaliers and the Bulls, the line was Cavs at -8.5 and they are playing at their home court.
The result was very disappointing, I thought they will deliver and give a good show to the fans, they loss against the bulls and they were dominated. It seems like they do not have the chemistry yet, Rose as a point guard now does not blend well on the system their coach has design.
It's not because of chemistry but pre season games is different from regular season. Look at how Cavaliers didn't able to force themselves to take up the lead again during end of third eventhough they can.
Plus can't imagined you take the risk of -8.5 spread for Cavaliers on pre season game. That was a risky pick mate.

There are a lot of surprises in this pre season so you cannot really rely on the odds alone and how good the team is.
Usually starters does not play hard to avoid injury and knowing this will give a gambler a chance to win betting on the bigger odds, just like today, the sixers are +7.5 against the Nets and it seems like they are winning this game so that's a good winning for those who take the ML.