In the case that we acquire Karlsson without giving up Sergachev, we could leave McDonagh unprotected and protect 7 forwards not named Tyler Johnson or Alex Killorn. I assume this would be enough to keep Cirelli and an additional young forward.
Protect:
Stamkos, Kucherov, Point, Palat, Miller, Cirelli, ?
Where ? = Joseph/Volkov/Stephens
Seattle would then have to choose between:
Tyler Johnson @ 4 years, $5M
Ryan McDonagh @ 5 years, $6.75M
Alex Killorn @ 3 years, $4.45M
One of Joseph/Volkov/Stephens/Cernak
So unless all of our AHL players pan out to be pretty good, we'd be in a position to shed one of Johnson/Killorn without giving too much as a sweetner. The quality of McDonagh's play in 2 years will also be a big x-factor. If he's in decline, this becomes an easier decision, if he's, say, a low-end #1 D still, this becomes much more expensive assets-wise.