If Kassian is traded, that's because Virtanen's making the team next season. We're short in blue chip defensemen prospects, so we could work a trade with a few teams. People want a Krug? Well how about just finding one to just sign? Boston did.
We're also short on RW prospects beyond Virtanen though. We have some two-way centers and some one-dimensional LWers. Not much on D. But does Kassian even have any value at this point?