The Red Devils have lost their last two league games to Manchester City and Watford, although Jose Mourinho's side (seventh) do sit above Leicester (11th) in the table, with the Foxes only managing seven points from five fixtures this term.
It was all pretty rosy for Man United in the early weeks of the season, with a Community Shield triumph followed by Premier League wins over Bournemouth, Southampton and Hull City. However, this is now a really testing period for the 20-time English champions after suffering three defeats in their last four matches in all competitions.
The Red Devils did return to winning ways on Wednesday night with a 3-1 success away to Northampton Town in the third round of the League Cup, but they entered that match off the back of a 3-1 defeat to Watford in the Premier League last weekend, which followed a 1-0 loss to Feyenoord in their first Europa League group match.
Man United have so often been known for their ability to bounce back quickly from defeat, but they do not seem to have recovered from the home loss to Manchester City after the international break. A record of nine points from five league games is not exactly disastrous, but they are already six points off leaders Man City, who look so dominant.
It does appear that it will be a fascinating battle for the top four this season, with Everton making strides under Ronald Koeman. The likes of Tottenham Hotspur, Arsenal, Chelsea and Liverpool are all currently above Man United in the table, but just two points separate seventh-placed Man United from third-placed Spurs.
Incredibly, Mourinho has actually suffered 12 defeats in his last 23 league games as manager. His previous 12 defeats came over a period of 110 games, which is an indication of the pressure currently on the Portuguese, who hit out at "football Einsteins" earlier this week during what is a difficult period for the experienced boss.
Man United have not lost two of their opening three home matches in a league season since 1986-87 and it is imperative that the hosts return to winning ways this weekend as they stare at a growing fixture list over the next few weeks.
Indeed, the Red Devils will welcome Zorya in their second Europa League group match on Thursday night, before hosting struggling Stoke City in the league next weekend. They will then travel to Liverpool on October 17, before hosting Fenerbahce in the Europa League and travelling to Chelsea on October 23. There is also the small matter of a League Cup fourth-round clash with Man City on October 26 as the games really pile up for Mourinho's side.
Recent form: WWWLL
Recent form (all competitions): WLLLW
It was always going to be a difficult season for Leicester after their stunning Premier League success last term, but Claudio Ranieri's side have made a solid start to the campaign, which has included their first ever Champions League fixture.
A shock 2-1 defeat at Hull City on the opening weekend of the Premier League season would have brought the Foxes back down to earth, but they put in a much better performance against Arsenal one week later to claim a point in a 0-0 draw. A 2-1 win over Swansea City at the end of August brought Leicester their first three points of the campaign, but they lost heavily at Liverpool after the international break.
The champions did record a 3-0 win over Burnley last weekend, however, to move into 11th position in the table on seven points. There will be no more League Cup football for the Foxes this season though after losing 4-2 to Chelsea in extra time on Wednesday night. In truth, it was a fixture that Ranieri's side did not need at this stage of the campaign.
Whatever happens this season, no-one will ever be able to take Leicester's first Champions League match away from them. It was a wonderful occasion for the club and indeed a brilliant result as they won 3-0 at Club Brugge. There will be tougher tests ahead, namely Porto next week, but Leicester showed that they can compete at that level of football.
Incredibly, Leicester only lost three times in the Premier League last term, but defeat at Old Trafford would be their third of this season, just six games in. Indeed, the Foxes have now gone four successive away matches without a win in the league.
That said, Jamie Vardy has scored in three of his four games against Man United in all competitions and new signing Islam Slimani, who netted twice on his Premier League debut last weekend, will enter the match having scored 22 times in his last 23 league appearances, which is a record that has been carried over from Sporting Lisbon.
Recent form: LDWLW
Recent form (all competitions): WLWWL
Anthony Martial revealed that he had taken part in training on Friday after recovering from the head injury that he suffered in last week's clash with Watford, but Mourinho has ruled the Frenchman out of contention with a separate injury.
Wayne Rooney's position in the team continues to be discussed and it was widely thought that Mourinho would drop his captain from the XI, but Martial's absence should see the England skipper keep his spot. Ander Herrera, meanwhile, could add an extra body in midfield alongside Paul Pogba and Marouane Fellaini.
As for Leicester, Kasper Schmeichel is expected to return between the sticks after Ranieri revealed that the goalkeeper, who suffered a concussion last week, had taken part in a training session on Thursday, although a muscular problem could yet rule the Dane out.
Vardy and Riyad Mahrez were both on the bench for the League Cup clash with Chelsea and should return to the XI, while Slimani is expected to keep out Shinji Okazaki despite the latter's two goals during the week.
Man United possible starting lineup:
De Gea; Valencia, Smalling, Bailly, Shaw; Pogba, Fellaini, Herrera; Rooney, Ibrahimovic, Rashford
Leicester possible starting lineup:
Schmeichel; Simpson, Huth, Morgan, Fuchs; Mahrez, Drinkwater, Amartey, Albrighton; Vardy, Slimani
Head To Head
Saturday will be the 123rd meeting between these two teams in all competitions, and Man United lead the head-to-head 61 wins to Leicester's 33. It is actually a rivalry that dates back to September 1894, when Man United recorded a 3-2 victory in Division Two.
Man United are actually unbeaten in their last seven home Premier League games against the Foxes - recording five wins in the process and only conceding four goals in that time. What's more, Leicester have won on just one of their last 18 league trips to Old Trafford and that success was back in January 1998.
We say: Man United 2-1 Leicester
It is not exactly a must-win game for Man United, but it is not too far from it. Leicester will be confident of upsetting the Red Devils this weekend, but we are backing the home side to pick up a much-needed three points, which would certainly ease the pressure on Mourinho.