Manchester United are working simultaneously on three centre-back deals.
This comes as United close in on the first signing of the INEOS era after a deal was agreed for Bologna striker Joshua Zirkzee.
Bayern Munich defender Matthijs de Ligt remains a strong option at centre-back and the 24-year-old is keen to join, with talks having been positive with the Bundesliga side.
De Ligt played under Man Utd boss Erik ten Hag at Ajax where they won the Eredivisie in 2019.
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Meanwhile, United are discussing whether to try again for Everton's Jarrad Branthwaite after having two bids rejected.
Everton turned down the latest offer thought to be in the region of £45m plus £5m in add-ons.
And in a third potential transfer, United are not ready to give up on Lille defender Leny Yoro despite his preference being a move to Real Madrid.
However, Lille would prefer for Yoro to move to Old Trafford as United have met their £42m (€50m) asking price whereas Real are yet to match the offer.
Yoro, 18, came through Lille's youth system to make his first-team debut in May 2022. Last season he played 44 times as Lille finished fourth in Ligue 1.
United would like to sign at least one of De Ligt, Branthwaite and Yoro although adding more than one of them will depend on departures.
De Ligt, 24, has spent the last two seasons at Bayern Munich since signing from Juventus, playing 73 times and scoring five goals.
Branthwaite played 35 times for Everton in the Premier League last season, although he was cut from England's Euro 2024 preliminary squad.
United want to replace Raphael Varane after he left the club following the expiration of his contract.
Victor Lindelof's future could be key. The defender has entered the final year of his contract and there are currently no talks planned over a new deal.
Talks continue with Jonny Evans and his representatives over a new one-year deal.
Strong interest also remains in midfielder Casemiro from clubs in Saudi Arabia.
Contacts through intermediaries have been made to explore the conditions of a deal, but United have yet to receive a formal offer.
Casemiro's future could have a big say in whether United enter the market in that position with Paris Saint-Germain's Manuel Ugarte one of several options
When does the summer transfer window open and close?
The 2024 summer transfer window in the Premier League and Scottish Premiership is officially open.
The window will close on August 30 at 11pm UK time in England and at 11.30pm in Scotland.
The Premier League and Scottish Premiership brought forward Deadline Day to link up with the other major leagues in Europe. The closing dates were set following discussions with the leagues in England, Germany, Italy, Spain and France.