On first thought it is surprising. But on second thought it would actually make a lot of sense.
Hyundai has seen after first rallies that they have a car capable of winning manu champ, but Paddon seems out of form.
So hiring Mikkelsen as 2nd driver and switching Paddon and Sordo on gravel/tarmac would maximize their chances.

That said no contract is signed. Hearing Mikkelsen, it seems he wants a multi-year deal. Signals from Toyota are quite mixed and Citroen's program/plans has been strange for quite a while so anything can happen. The only team out of question is definitely Ford, pretty sure they have enough issues with finding money for Ogier+car development and desperate in trying to keep him for more than 1 year.
Interesting times anyway.