Newcastle have agreed terms with Atlanta United over a club-record deal for Miguel Almiron, Sky Sports News understands.
It is understood the MLS midfielder is travelling to the UK on Tuesday night for a medical.
The transfer fee is understood to be around the £20m mark, which would surpass Newcastle's current transfer record of £16.5m paid for Michael Owen in 2005.
Atlanta valued Almiron at £30m at start of window, but have lowered their valuation since then, with Almiron still to agree personal terms.
Rafa Benitez said earlier this week that Newcastle were still working on multiple deals before Thursday's transfer deadline, but on Tuesday offered no guarantees regarding his own future at the club.
Newcastle are in talks with Benfica over a loan move for midfielder Andreas Samaris, Sky Sports News understands.
They are also in negotiations with Monaco over a similar loan deal for Italian defender Antonio Barreca.