Nothing to really wonder about. He's going to have good games/stretches and bad ones. Just like everyone else. If he started the season "hot" and remained hot the whole year then he'd be a better player than he actually is. He's a useful player and should be in the lineup pretty much every day.
The problem is that Stalberg has pretty much had more bad games than good games this season. Plus, he's a veteran player and has been dragging down his linemates, who are much more inexperienced, not what you want to see from a veteran. I'm not happy with his play at all. But, he's never really been able to show very much since he left Chicago 2+ seasons ago.
I think Hayes/Miller and Lindberg would be much better off with a more consistant linemate. I'm hoping Fast moves up and Etem slots into the 4th line tomorrow.