Everything I've ever heard (including a couple of personal NHL relationships) is that you never harm a player's development by being exposed to the best league in the world, on AND off the ice. Sure, he only played one (?) game...but going on the road trip, seeing the rest of the roster's work habits, game prep, pre- and post-game attitudes....that can't be a bad thing.
The most important thing isn't how it affects Necas' season in the Czech Republic; it's to ensure there are no surprises when he comes back over here. When that happens, Necas will be expected to make the team. That alone will be enough on his plate; for there to be no surprises, that is huge.