Chelsea will use their incoming Champions League quarter final against Real Madrid to make a final decision on Joao Felix.
The Portuguese international has impressed Blues head coach Graham Potter in the early stages of his stint in England, following a January loan move from Atletico Madrid.
Los Rojiblancos are willing to sell Felix to Chelsea, despite opting against a purchase clause in the original deal, as his relationship with the club has reportedly broken down.
Diego Simeone has set an £80m asking price for the former Benfica winger with Potter and Chelsea willing to match their valuation.
However, club owner Todd Boehly is still assessing the transfer details, and the two legs against Los Blancos could be a vital testing ground for Felix, according to Marca.
Chelsea meet Real Madrid in the Champions League knockout stages for a third successive season and Potter wants to see if Felix can make a decisive impact on the big stage.