I think we need a bit more info on your league. Is this a cap league? Auction league? What else is available in the draft? it's all about context.
More specifically about him, his 1.13 or whatever it was shot on goal per game rate last year is something to red-flag and watch. I own him in one dynasty and I need that to catapult up to 140+ this year for me to relax. Jake Gardiner and Ryan Suter were the only two Dmen to hit 50pts without averaging 2+sog/gm. So it can be done, but he needs a 70% increase in SOG to give himself a chance.
Part of this could simply be - being a rookie and making the right play - letting the vets make the final decisions? I hope so.. If the shot totals jump - then I'm comfortable in saying he's a 40+pt threat this season. If they don't take that necessary jump - to at least Gardiner's level (133) then 35pts at best.
Everyone hypes the crap out of him - but if this isn't just a rookie anomaly - then when does it become a wart? Someone's going to think - he was paired with Chara so always passed off to him - I guarantee Chara more than once last year skated by him during a stoppage and said, 'kid - take the shot'