Barcelona sporting director Robert Fernandez hopes a deal for Valencia striker Paco Alcacer can be done in the coming days.
Alcacer, 22, has emerged as Barcelona's top target, and Catalan newspaper Sport reported that the player has agreed terms.
Robert would not reveal how close a deal was to being completed, but added: "The market is open until Aug. 31.
"We're very interested in Paco. We're working on it, but we can't say more at the moment."
Robert said it will be "Alcacer or no one" but added: "I am always optimistic and I work with the aim of getting things done, but it's not easy because it's difficult to come to Barca.
"We have a team which is difficult to improve and that makes it even more difficult. I'm optimistic, and we'll exhaust all options until the final day of the market."
Meanwhile, Valencia coach Pako Ayestaran has said he would include the Spain international in his squad for Saturday's trip to Eibar, although Arsenal target Shkodran Mustafi will not make the trip.
Valencia newspaper Superdeporte reported that the striker has made plans to give a news conference in the coming days to explain his reasoning for leaving.