River own 90% of Carrascal’s economic rights but still owe €2.5m to his former club, Karpaty Lviv.
Carrascal, 22, only joined River in December after they used an option to buy him following a loan spell.
They now have the opportunity to make a quick profit on the Colombian attacker with CSKA readying an ‘important’ offer.
The Russian club are looking very closely at the Argentine market for potential deals.
Gaichi could travel to Russia next week to finally complete an €8.5m move to CSKA.