There's a middle way, which is to let him play out this season and then offer him a max deal before free agency opens assuming he actually proves that last year's 20 games wasn't any sort of fluke. That way, Portland minimizes their risk, but doesn't tell a star player to hit the bricks and find a max somewhere else before Portland matches it.
If just making him play out his first contract is the problem, then that's tough luck, I guess. I wouldn't be comfortable handing a max deal to a player who's had injury issues and only 20 games of max level play. It would be different if he had unrestricted free agency coming up, but giving up the chance to ensure he is what he appears to be would be more risky than the good feelings would be worth, IMO.