Ah, I forgot about Gunnarsson.
Just curious, is it purely a number games with Schmaltz or is it a mix between that and not gaining Yeo's trust? I know for the Avs Bigras had a bit of trouble transitioning to the NHL and didn't warrant enough for Bednar to trust him.
I think it's mostly a roster composition issue at the moment. One of Dunn or Schmaltz was going to make the team this season with the other six defensemen already set in stone. Dunn's easily the more dynamic of the two, and he ultimately won the job. Bortuzzo and Gunnarsson have played well for the Blues, and Bortuzzo is the sort of physical guy who's traditionally paired with a slightly undersized defenseman like Dunn to help balance the pairing, so it made a lot of sense to send Schmaltz back down and let him play.
I think Schmaltz is good enough to play in the NHL right now in a bottom pairing role, with middle pairing upside that's basically tied to the consistency of his play at the NHL level. I think his game is too well-rounded to be a career AHLer. The flip side is that he's not really outstanding at anything, so his usefulness in any given role is more likely to be defined more by what a defense is lacking around him than it is by him taking jobs away from others.
Once he has some time to adapt, I think he will probably be one of those solid depth guys who is quietly functional in most any role, but rarely your first choice for any of them. How valuable that is will depend on what's ahead of him on the depth chart.