Barcelona attacker Arda Turan welcomed his agent, Ahmet Bulut, to the city last week.
Sport says Bulut arrived armed with a lucrative offer from China.
The proposal comes from Guangzhou Evergrande and is worth €20 million-a-season. Guangzhou are also willing to pay Barca €50 million to sign the Turk.
Turan had rejected an offer from China before Christmas, but is now rethinking his stand.
For their part, Barca will only deal with Bulut, with several rival agents attempting to muscle in on negotiations.