Apparently they want both. Will Fabian or Soler be called up for the WC?
Soler has been present in the squad since the Euro's. LE will probably go with whoever is in better form as the 6th choice mid, but Soler has been better for Spain under him and I think LE prefers him.
I'm reading Soler is the plan B to Ruiz for you, but with expiring contracts both are opportunities in the market. You don't really need both though, but if you got the budget then why not I guess.
Don't get me wrong though, he is a good player who might turn great with better players around him as he shines more for Spain. But for a PSG team with Verratti as the key mid, and setup to protect and provide to the three attacking cracks then a Fabien Ruiz on form is more suitable.