Canes aren’t going to move Necas for someone who would be playing 3LD for them.

I mean value wise it works but I highly doubt they want multiple B-assets for a A-player, Matheson isn't moving the needle for them as they already have veteran that fill the similar role (Skjei, Slavin).

Probably Mailloux or Hutson for replacement of Burns would be something they would want as a package for Necas

Matheson would be #1LD - you can argue him all the way to 2LD and be wrong if you want.
Also Skjei expires this season, Slavin and Orlov next season. You would be left with 1LD and a very possible 2LD or 3LD (based on Canes depth) when the other 2 are gone.
In saying that, I am not sure this trade is valued enough to get Necas.

Considering that he wouldn’t be playing above either of Slavin or Orlov next season, and in all likelihood end up as a scratch when Nikishin comes over next season, what point is there for the Canes to make this trade? Not to mention, assuming that Orlov doesn’t get extended, he would only remain a 3LD behind Slavin and Nikishin. It’s just not worth moving Necas to only bring in someone who likely won’t play anything outside of 3LD barring injuries.

If the Habs are wanting Necas, they would have to buy off a contender. Canes already have enough futures as it stands. So Habs management would need to have a very uncomfortable conversation about moving one of Suzuki, Caufield, or Slafkovsky in order to get Necas. Outside of that, it makes no sense for the Canes to move Necas.

Start with Caulfield then we’ll talk