West Ham are discussing personal terms with Said Benrahma over his proposed £30m transfer from Brentford.
The 25-year-old will take a medical in next 24 hours if and when personal terms are agreed.
West Ham are increasingly hopeful Benrahma can complete his move ahead of Friday's deadline having agreed a deal with Brentford earlier this week.
Discussions between West Ham and Benrahma are over a five-year deal.
Earlier on Wednesday, Benrahma held a meeting with Brentford officials to try and resolve a dispute over a payment he believes he is owed.
Benrahma scored 17 goals in 46 appearances for Brentford last season as they reached the Championship play-off final before Thomas Frank's side were beaten by Fulham in extra-time at Wembley.
Meanwhile, West Ham remain interested in Bournemouth forward Joshua King despite having had a £13m bid for him rejected at the weekend, with the Championship club valuing the Norway international at around £18m.
King, who has one year remaining on his contract, has scored 48 Premier League goals for the club since joining in 2015.
A domestic transfer window between Premier League and EFL clubs remains open until October 16 - dubbed Deadline Day Two - but how does it work?
The international deadline - where English clubs could buy, sell and loan players from abroad - closed on October 5, but an agreement between Premier League and EFL teams means players can still be transferred in England.
Following consultation between the leagues - and because FIFA allows a summer transfer window to run for up to 12 weeks - Premier League clubs can still do business with EFL sides for a further 11 days in a bid to bolster their squads.
They can make loan or permanent signings, as well as selling, but there cannot be transfers between Premier League teams.
All EFL clubs can still do domestic business with any English team up until Deadline Day Two on Friday.
The domestic transfer window will run until 5pm on Friday, October 16.