United have until 5 p.m on Thursday to add new players ahead of the start of the season. Mourinho spent much of United´s pre-season tour of the United States grumbling about the lack of depth in his squad and reportedly feuding with executive vice-chairman Ed Woodward over failed approaches for defenders Harry Maguire, Yerry Mina and Toby Alderweireld.
Manchester City are favourites to be the first team since Neville's United to retain the Premier League, with the chasing pack hoping that a renewed focus on the Champions League might lead to City taking their eye off the defence of their title.
"The market closes today".
'I said during pre-season - it looked like I was saying something absolutely out of order, something insane - but I repeat: pre-season is hard when you don't have your players to work, it's as simple as that'. I don't think just because they haven't signed a centre-back we should be sat here thinking "We'll let Manchester United off the hook, they shouldn't be challenging this year".
Indeed, players who are free agents can also be signed up until the August 31 deadline, meaning the Seasiders and Town will have no need to stress if they can't bring in any new faces before the August 9 window closes.
Mourinho revealed he will be without six senior players for the game against Leicester.
"Unavailable is Romero - he had a surgery after his injury before the World Cup".
"So I will have to focus on the players I have and in relation to this first couple of matches, maybe four matches because after Burnley there is national team and a couple of weeks to recover people and prepare people better, is to focus on players available so I'm not thinking about that list I give you, I focus on what we have".
Mourinho will have to decide whether or not to pick Jesse Lingard, Paul Pogba, Ashley Young and Marouane Fellaini against Leicester after they returned from post-World Cup break on Monday. "They trained on Monday, Tuesday, Wednesday and today, so you can imagine that they're not really fit and ready, but we have needs", said the boss of the quartet.