The centre-back position didn't become an issue until this summer and since then the club's hierarchy have felt that the options open to them have not warranted the investment required.
United had seven players involved in the final weekend of the World Cup with Romelu Lukaku, Marouane Fellaini, Phil Jones, Marcus Rashford, Ashley Young, Jesse Lingard and Paul Pogba representing the club and set to return late.
In the campaign prior to that, United made complete mincemeat of their opponents by beating them 4-1.
Speaking at his press conference ahead of the Premier League opener between Manchester United and Leicester on Friday, Mourinho was in a defensive mood about the criticism his United team got for finishing behind a massive 19 points behind Pep Guardiola's record-breaking City side.
In reality an intermediary had contacted United a few days earlier asking whether they would be interested in the experienced 32-year-old.
But I am astonished, astonished that a club of their ilk, a club with their clout, a club that were so far off the pace past year in terms of the points gap, that they have done little or nothing.
Leicester manager Claude Puel: "We lost Riyad Mahrez, who was a very valuable player for us, so it was important to keep our best players and have good additions to the squad".
On Thursday, however, the Mirror reported that Pogba does not want to leave the club that signed him from Juventus prior to the 216-17 season.
"If they feel they can help us, 20 minutes, 10 minutes, half an hour".
He also said that there should be no discussion about it being okay for United merely to make the top four in the English Premiership, that would guarantee Champions League football stressing that they should be aiming much higher. Even the statistics, as great as they are, do not equate to the gulf.
"He didn't have a pre-season, three days of pre-season", Mourinho said.
"I'm not confident", he said.
"I like my players and my group".