It's just a single pre-season game, let's not over-react.
Actually I like betting on preseason games because I don't need to analyze it carefully since I observed that the underdog and the over usually hit. (this tip is for bettors, and I believe most of us here are betting as well).
Are there any lines open for pre-season betting in any sports betting website?
You can check sportsbet.io and see for yourself. I mean, try doing some research on your own and avoid asking questions which you can find answer for yourself.
I keep betting in playoffs and I used sportsbet but I'm pretty sure other websites has this kind of line, just go check it if you haven't check yet.
And you can also check this thread for NBA betting - https://bitcointalk.org/index.php?topic=5091185.new#new