The English transfer window slammed shut on Friday evening, bringing an end to a record-breaking summer for the Premier League.
Clubs from the English top-flight spent £2.36bn on transfers, surpassing the previous record that stood at £1.8bn.
Man United were among those who splashed out during the summer, spending a total of £176m, including £72m on signing striker Rasmus Hojlund from Atalanta.
While the Red Devils made seven additions to Erik ten Hag's squad, they also saw several players depart the club on permanent or loan deals.
Van de Beek and Bailly were expected to be among the departures, but they failed to secure a move away before Friday's deadline.
However, according to Manchester Evening News, there is still a possibility that the duo could still leave the club next week.
Van de Beek has struggled to find his best form since completing a move to Man United from Ajax in the summer of 2020.
The Dutchman, who has made 60 appearances for Man United, has been deemed surplus to requirements at Old Trafford, which has led to links with clubs across Europe.
Van de Beek reportedly turned down a loan switch to French side Lorient, but talks have taken place with Galatasaray over a potential deal.
With the Turkish transfer window open until September 15, there is still time for Galatasaray to agree a deal to sign the 26-year-old.
Bailly, meanwhile, returned to Man United at the end of last season after spending the campaign on loan at French side Marseille.
The Ivory Coast international is behind the likes of Raphael Varane, Lisandro Martinez, Harry Maguire and Victor Lindelof in the pecking order at Old Trafford.
As a result, he does not feature in Ten Hag's plans and will be allowed to leave the club if he can find a new destination.
A move to the Saudi Pro League has emerged as a possibility and with the Saudi transfer window open until September 7, there is still time for a deal to be completed.