He's only been an NHL regular for the past 2 seasons so I'm a little confused at your first comment. In his first pro season (2011-12) he played 62 games between the NHL and AHL. He has played 60, 70, 75 games since then, up until last season when he was out half the year with a concussion. He received the concussion from a dirty hit by Tyson Barrie. Not the worst hit ever but it was high and late and he was a vulnerable target...all the things the NHL has been trying to get out of the game. If you want to say that his lengthy recovery is a sign that he may be concussion prone, that's your opinion and you are welcome to think that, but don't tell me he has only played 40 games in a season once, or that he is on some Beau Bennett level of injury prone, whatever that may mean to you.
He played 75 games in 14/15 and looked really good once he came over to Anaheim. Last year was basically a lost season for him. If he was on the NJD he would be a 2nd pairing defenseman for them, as he was for the Ducks prior to injury (avg 19 minutes a game)