AC Milan are facing competition for the signing of Porto striker Jackson Martinez, who has also been linked with Arsenal and Valencia.
Colombia international Martinez, 28, is set to leave Porto this summer and Milan general manager Adriano Galliani had flown out to Portugal to try to negotiate a deal.
However, he did not return to Italy with an agreement in place, and the player's agent, Luiz Enrique Pompeo, said that is because the player has another option.
"He likes Milan a lot -- they are a top club -- but on the other side of the scales, we have another offer from a top club," Pompeo told calciomercato.com. "I cannot confirm that it's Valencia, but it's definitely a top club.
"We're working on the basis of a four-year contract and I've got to see Galliani again either tomorrow or the day after. There are still a few things to sort out and an agreement has not yet been reached."
Galliani, meanwhile, is quoted as telling La Stampa: "The negotiations are difficult. There are various clubs interested in the player and his personal preference is going to be crucial."
Earlier, Pompeo told O Jogo that Martinez's future "is pretty much decided."
"Things should be resolved in the next few days," he said. "He's going to a top European club, which will be announced as soon as the contract is signed.
"Negotiations have been underway for a few weeks -- there are still some details to be resolved, but then Jackson Martinez's departure from Porto can become a reality."
The Daily Mirror has reported that Arsenal are keen to sign the player, who is expected to cost €35 million, but only if they can offload Lukas Podolski, Joel Campbell and Yaya Sanogo.
Milan, meanwhile, should be able to meet the player's asking price, with club president Silvio Berlusconi having promised to invest heavily in the side after two disappointing seasons in which they have missed out on European football.
Thai businessman Bee Taechaubol has secured an exclusive period of eight weeks in which to negotiate a 48 percent stake for a reported €500 million, which is set to increase the funds available for transfers.
Taechaubol posted an Instagram picture on Wednesday showing Galliani and Doyen Sports chief executive Nelio Lucas on a plane with the message: "Nelio Lucas and Adriano Galliani -- building together under the guidance of the President."