Barcelona have opened negotiations with Atletico Madrid over a swap deal involving Joao Felix and Antoine Griezmann, various sources have confirmed to ESPN.

Barca failed with an offer to take Felix on loan on Monday, with Atletico knocking them back immediately, but returned on Tuesday with a new proposal involving Griezmann.

Felix's agent, Jorge Mendes, is working as an intermediary on the operation, while sources close to Griezmann say a deal is not "impossible."

However, sources involved in the negotiations acknowledge it will be difficult to sort out so close to Tuesday's transfer deadline.