Ruben Amorim has said the financial reality at Manchester United means that players will have to exit Old Trafford in the summer before the club can strengthen the squad.
United secured loan moves for Marcus Rashford, Antony and Tyrell Malacia in January and brought in youngsters Patrick Dorgu and Ayden Heaven from Lecce and Arsenal, respectively.
Amorim is keen to keep reshaping his squad in the summer, but the 40-year-old said pressure from financial restrictions means there will have to be departures first.
"Here it is simple, to do something we need to sell players," Amorim told a news conference on Friday.
"The window is closed, we have to focus on the next game then in the summer we will see."
Sources have told ESPN that United are not ruling out further job cuts to club staff in an attempt to balance the books. More than 250 employees have already been made redundant since Sir Jim Ratcliffe took control of football operations nearly a year ago.
"I have to understand all these problems but that problem of our club is not new," Amorim said.
"We already knew all the rules of [Financial] Fair Play but that cannot change the way I coach the team. Our biggest problem now is Tottenham [on Sunday]. We know with the moment of the club."
Amorim has seen Antony make an impressive start to his spell at Real Betis with two goals in three games. Rashford looked lively as a substitute on his Aston Villa debut and Scott McTominay is thriving at Napoli.
"Sometimes it's like that," Amorim said.
"It can happen in any club. This is a club with a lot of pressure and in this club you have to have a base with younger players, talented players, coming to a team with one strong base. At this moment we don't have that.
"You feel it in Dorgu. He was a little bit nervous in the first moment.
"With a strong core that can cope with this like it's supposed to be in this club it will be more easy for the players to play football, but you need to cope with the pressure. Sometimes they go to other clubs and are freer with no pressure."