I'm pretty sure there will be a demo online. As they did with Pulse.
The game is a PSN game only and I'm pretty sure Sony has high expectations of the online gaming part of WOHD.
I'm sure Sony want others to download the game and to push the PSN-Store. And the best and easy way to do so is a free demo.
This demo should have online play of course so the customer has an impression of what to expect from the full game.