So, I'm going to say it's out of the realm of possibility, because it would absolutely handicap Anaheim's future. If they win a Cup, hey, that's great, but no matter what happens after, they are in a really ****ty position. Winning a Cup would, arguably, make it worth it, but the fact is the odds don't favor them doing that.
I'm a big McDonagh fan, but I'm not willing to see Anaheim offer up their future for 1 year of McDonagh, and the rest of this season. If another team is willing to make that deal, they are welcome to McDonagh, but I don't think it will happen. You'll see something else instead of that second high value prospect. A rostered player, maybe. Maybe a team like Tampa would be willing to do it, but that would be because their team is currently loaded with young talent that they can be confident will be around for at least a little while. But really, I think you'll get a return worth less than that from them too.