If it's a short-term sub, wyrm or not shouldn't be a problem. Alneyan could maybe even do it real quick-like. Nothing of great consequence is going to happen in the first couple turns anyway.
Well, aside from my brilliantly appropriate Robert Frost quote...
If it would be a longer-term sub, it might as well be a replacement, in which case it's not a big deal to wait for the new Mictlaner to put together a pretender and restart the game.