Weal had to get a lot stronger to handle the NHL, and Martel is significantly smaller than Weal. It will be hard for him to play in traffic. Two or three years ago Martel would have probably already been called up, but now it's going to be tough to find a spot, which is why an injury to Weal or Konency is his best shot to get a cameo and prove he belongs. If Leier gets hurt they'd be more likely to bring up NAK or MV and put Raffl at LW, or bring up Vorobyev and put Laughton at LW.
Sure he's more talented than Lehtera, Weise or Read right now, but what line do you put him on?
Martel - Patrick -Konency? That's asking a lot of Patrick.
Martel - Filppula - Simmonds, at least teams won't mess with him too much, but then you have Weal with Patrick and Konecny.
Either way we'd have an undersized middle two lines without the great speed to compensate.
This is why Lindblom will get called up instead of Martel, once he's ready you could play him anywhere in the top 9, and even on the checking line.
Martel might be a better fit next year when Patrick is a year older (and stronger) and Vorobyev replaces Filppula (who isn't very physical). It's just a matter of finding balance on the #2 and #3 lines.