At 6'3" and 215 pounds, Kassian is the most NHL-ready prospect in the draft. His offensive upside may not be as great as some of the other prospects but he makes up for that with size, speed and strength. He is everything the Sabres are not. Big, strong and tough.
The knock on Kassian though is that sometime he will take a shift off, and that is really the last thing this Sabres team needs.