Lisandro Martinez has asked to leave Ajax this summer amid interest from Manchester United and Arsenal, say reports.
The Argentina international is at the centre of a bidding war between the two Premier League rivals.
Recent reports said United have made a £37 million bid for Martinez, after Arsenal had two offers rejected by the Amsterdam club.
According to TalkSport, the centre-back has tried to hurry along a move by submitting a transfer request.
Ajax have set a £40m price tag for the 24-year-old, who won the Eredivisie title under now-Red Devils manager Erik ten Hag last season.
The 24-year-old’s relationship with Ten Hag has bolstered confidence at Old Trafford that they can get a deal done, but the Gunners won’t give up without a fight.
Tyrell Malacia became United’s first signing of the summer earlier this week when he arrived from Feyenoord.
But the Red Devils have failed to complete any other deals so far, with long-running talks for Barcelona midfielder Frenkie de Jong still ongoing.
They were interested in Martinez’s team-mate Antony, but had a bid turned down after falling well short of Ajax’s asking price for the Brazil international.
More Manchester United stories
Frenkie de Jong has been United's top target this summer and the Red Devils are close to agreeing a deal - although they remain willing to walk away if the price isn't right and Harry Maguire even came up in talks at one point.
A bid has been submitted for Ajax defender Lisandro Martinez, while United are closing in on Feyenoord left-back Tyrell Malacia.
Marco Asensio of Real Madrid has emerged as a surprise target, but Erik ten Hag will have a budget of just £100 million to work with this summer.
