There's no way we'd retain on Matheson. He's not even making $5m. In UFA, he's easily looking at more than $5m.
Gallagher has a full NMC & he doesn't seem interested in moving, especially now that he's married to a Montreal girl & has a newborn.
I guess if we move Anderson at the draft.
The retain on Matheson wouldn't be to make him tradeable, it would be to maximize his value.
Imagine a contending team adding a 2.4ish million top4 D like Matheson BEFORE making their summer shopping.
Anderson/Gallagher trades can wait for the Petry/Allen retention to expire.
The only other possibilities (except the obvious core) are Laine, Xhekaj, Dach or Newhook. I don't see them needing to use it on Xhekaj/Dach/Newhook so the only other option from then ones previously mentioned is Laine and I don't see them trading him.
For Gallagher, I could see him wanting to move back in west Canada to Vancouver or Edmonton.