Barcelona must make include players in their offer for Sevilla defender Jules Kounde.
The France international is a target for Barca this summer, with Sevilla demanding in the region of €60m to sell.
Barca do not have the money available to meet Sevilla's valuation in a straight cash deal and instead are planning a swap proposal.
Mundo Deportivo says Konrad de la Fuente, Francisco Trincão, or even Clément Lenglet, are being discussed as possible makeweights.
Kounde said last week: "I am already in a big club, but I would like to evolve in an even bigger club. We'll see what the future holds, but it's something that remains in my mind."