Liverpool are currently attempting to sign Colombian winger Luis Diaz from Porto.
If completed, the transaction is expected to be worth €45 million (£37 million), plus a maximum of €15 million in potential bonuses.
Liverpool had planned to wait until the summer but changed their mind after it became clear that Diaz would leave if they did not act.
Tottenham, who reportedly had a bid of around £38 million rejected, had been linked with a move for the 25-year-old.
Diaz was Liverpool manager Jurgen Klopp’s first choice for the summer when the asking price was €60 million (£49.9 million).
However, with Liverpool moving late due to the possibility of missing out on Diaz entirely, the proposed move is far from simple.
The forward is currently with his national team for World Cup qualifying matches; Colombia plays Peru on Friday before traveling to Argentina on Tuesday, February 1st.
Liverpool will send a delegation to Argentina to conduct a medical in order to complete the transfer before the January transfer window closes on January 31 at 23:00 GMT.
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Diaz has faced Liverpool twice this season in the Champions League, with Porto losing 5-1 and 2-0 in the group stages.
Porto were eliminated from the competition after finishing second in their group behind Liverpool and Atletico Madrid.
They are, however, top of the Portuguese top flight, with Diaz scoring 14 goals and registering five assists in 18 league appearances.
If the deal is completed this window, it will be viewed as a major coup for Julian Ward, who will take over as Liverpool sporting director when Michael Edwards steps down in the summer
Ward was the driving force behind Diaz’s move, and Edwards was a key supporter.