The Red Devils have already strengthened their defence with the recent addition of 18-year-old centre-back Leny Yoro.
Man United have paid a reported initial €62m (£52.2m) for the Frenchman, who was heavily linked with a move to Real Madrid.
Although they have secured Yoro's signature, the 20-time English champions are still seemingly keen to sign at least one more centre-back this summer.
The Red Devils have seen Raphael Varane and Willy Kambwala leave the club, while it appears likely that Victor Lindelof will also be moved on.
Hoeness addresses De Ligt future
De Ligt appears to be among Man United's top transfer targets, with the club keen to reunite the Dutchman with his former Ajax boss Erik ten Hag.
The Man United head coach recently commented on the transfer speculation, confirming Man United's interest in signing the Netherlands international.
Bayern's honorary president has now spoken out on De Ligt's future, admitting the defender could depart the Allianz Arena this summer.
"It is possible that a defender will still leave," Hoeness told Sky Sports Germany. "De Ligt is Dutch, the coach at Man United is Dutch. I would have no problem if he stays. Personally, I would not sell (Dayot) Upamecano."
Are Man United close to agreeing a deal for De Ligt?
De Ligt is believed to be keen to complete a move to Old Trafford and has already agreed personal terms with the Premier League giants.
While the player is open to the transfer, Man United are yet to reach an agreement with Bayern over the potential move.
There is a belief that the Red Devils are focused on selling players before they can look to sign another defender.
De Ligt, who is under contract until June 2027, has made a total of 73 competitive appearances since joining Bayern in the summer of 2022.
Having previously played for Ajax and Juventus, a move to Man United would give De Ligt the chance to compete in a fourth different European league.