Manchester United are expected to strengthen over the summer after failing to challenge rivals Manchester City for the title.
They are set to face Chelsea in the FA Cup final in May - but currently lie 16 points behind City in the Premier League table.
Jose Mourinho admitted that it might well be "very difficult" to catch Pep Guardiola's runaway league leaders next season.
Mourinho said: "Can we improve next season? Let's try.
"Can Manchester City keep this level or improve this level? Only they can say.
"But if they have the team they have and if they are going to invest on top of the team they have of course is going to be very difficult for us."
Mourinho will surely be pressuring the Man United board to spend heavily in order to compete with their Manchester rivals.
Replacing two players
The 55-year-old Portuguese coach revealed exactly which Man United players need to be replaced over the summer.
"We are going to invest the basic to improve our squad," Mourinho said, as per the Manchester Evening News.
"We need to find a replacement for Michael Carrick. If Marouane Fellaini leaves, we need to find a replacement for Marouane Fellaini."
Carrick, 36, is set to retire in the summer so at least one central midfielder will definitely be incoming at Old Trafford.
Fellaini, who is also a central midfielder, has rejected a new contract at Man United and appears likely to leave as a free agent this summer.
Surprisingly, Mourinho did suggest that some younger players will be given an opportunity instead of spending so heavily in the transfer market.
Mourinho continued: "There is always in the group of players, in the squad, there is always a player or a couple of players, they are not playing a lot, and they will try obviously to leave.
"So we are going again to touch our squad and to believe that more than spend, spend, spend, is probably the evolution of our players.
"We have some young players that need to get with both hands opportunities with their evolution, so let's see."
Scottish midfielder Scott McTominay was promoted to the first team by Mourinho this season - and was even sometimes preferred to club-record signing Paul Pogba.
The Red Devils are yet to win a league title since Sir Alex Ferguson retired.
Is Mourinho the man to bring success back to Old Trafford? Let us know what you think by leaving a comment below.