Liverpool are trying to sign Colombia winger Luis Diaz from Porto in the current transfer window.
The deal, if completed, is expected to be worth €45m (£37.5m) plus a maximum of €15m in potential bonuses.
Liverpool were planning to wait until the summer but changed their stance as it became clear that Diaz could move elsewhere if they did not act.
The 25-year-old had been linked with a move to Tottenham, who reportedly had a bid of around £38m rejected.
Diaz was Liverpool boss Jurgen Klopp’s first choice for the summer when the asking price would have been €60 million (£49.9m).
However, with Liverpool moving late because of the prospect of missing out on Diaz altogether, the proposed move is far from straightforward. The forward is currently with his national team for World Cup qualifying matches; Colombia play Peru on Friday before an away game against Argentina on Tuesday, 1 February.