I think the trouble with this trade is that Mantha hasn't had the raw production due to his injuries. If he manages to stay healthy for a full season and maintain his pace of the last few years, then his value will be much higher. So I'm inclined to wait until he does that to move him if we do. As is, it would take adding a significant piece (4 OA) to pry Werenski away from Columbus, and I really don't want to do that as we're taking 2 steps forward, 3 steps back. We really need to get a significant piece with 4 OA this year and build around that player. We're in no rush to compete so losing out on total value for the already performing defenseman isn't worthwhile. I'd rather have Drysdale and Mantha than Werenski as I think ultimately it's more total value. There's more risk, and the value is delayed, but we're going to be bad regardless so we have to take bets like that.
If we could trade Mantha + Rasmussen + Lindstrom for Werenski, then I'd definitely do that, but I don't see Columbus taking that deal until Mantha shows he can produce over 82 games (not to mention the value gains Ras and Lindstrom could make). Unfortunately, I think that our rebuild is coming along sufficiently slowly that there's a good chance we have to move Mantha eventually, but I don't think we should do so yet. I'm willing to bet his value will climb some more and I want him around so that Larkin, Zadina, Seider and 4 OA can play with some talent and suffer a little less.