Two players have already left the club in Kevin Gameiro and Mangala, so essentially Valencia CF is a central defender short and an attacker short. Don't forget that Valencia CF has to get 30 million euros to balance the budget so that means more players leaving.
Since Valencia CF doesn't have any money for player transfers unless they sell big and the only player worth more than 30 million euros right now is Goncalo Guedes which I believe would be a mistake to sell. This leaves the club with the only other option available and that is loan deals. Peter Lim and the club management plan to add replacements and fill up the squad with loan players who have cheap purchase options at the end of their loan deals.
My prediction and the most likely case would be Maxi Gomez and Kang-In Lee leaving for a combined 35 million euros. Now we cut one of the biggest salaries in the club, that basically frees up over 15 million euros, so Valencia CF could make a discovery in the second division and search for bargain players. But even at bargain prices we are looking at at least 5 million euros for players, possibly more if they've had an excellent season.