I suspect the injuries are playing a big part in why he's struggling. He's been injured a lot over the last number of years, and sometimes a player who misses so much development time either can't regain their form because they are rehabbing injuries while others are improving their hockey skills or it takes a year or two to get their game back up to form when sustaining such major injuries. It also looked like he was playing on the 4th line last I remember, so I don't think the role is helping.
I wouldn't write the guy off. He's only in his second season. He has another two and a half, and then he can make his way through the minors. He certainly has the raw talent to be a good NHL'er, but he needs to stay on the ice, and build up some better play.