Las Palmas sporting director Toni Cruz has confirmed that a "full agreement" has been reached over the sale of Roque Mesa to Swansea City.
The Welsh outfit are expected to hand over £11m for the midfielder, who had previously been linked with a summer switch to Atletico Madrid or Roma.
Mesa is to finalise a move to the Liberty Stadium on Wednesday, becoming the Swans' second arrival of the window following the earlier capture of goalkeeper Erwin Mulder from Heerenveen on a free transfer.
Speaking at a press conference on Tuesday, Cruz stated that "there is already an agreement for the transfer of Roque to Swansea" and that it "will be made official tomorrow".
Mesa has attracted high-profile admirers due to his impressive passing stats, finishing behind only Sevilla ace Steven N'Zonzi in terms of passes completed in La Liga last season.