United spent over £150million last summer to bring Zlatan Ibrahimovic, Paul Pogba, Eric Bailly and Henrikh Mkhitaryan to Old Trafford.
And a similar outlay has been predicted for this summer's transfer window as Mourinho tries to get United back on top.
Manchester United predicted team to face Watford
Fri, February 10, 2017
Express Sport brings you Manchester United's predicted team to face Watford
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Who will Jose Mourinho start against Watford?
Atletico Madrid star Antoine Griezmann is top of Mourinho's wishlist as he aims to strengthen his attacking options.
While Monaco's Tiemoue Bakayoko and Benfica duo Victor Lindelof and Nelson Semedo have also been linked with Old Trafford moves.
But Mourinho says that although incomings can be expected, there will not be a big overhaul of players.
Manchester United boss Jose Mourinho
He said: “We have a squad that, like every squad, needs changes but we know also that our squad has potential, our squad has good players.
"Some players will leave, some players will come but in a very natural way.
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"Everything is balanced and I think our summer [activity] will be quite small."