Ruben Amorim has not even reached a year as Manchester United manager and he is already under huge pressure for his job.

United's 3-0 defeat by Manchester City on Sunday has seen a fresh wave of doubt over his future in the role. The loss not only surrendered local bragging rights, it meant United's worst start to a season since 1992/93 and left Amorim's record at eight wins from 31 Premier League matches since he arrived last November.

Wayne Rooney has been among the high-profile names to openly question Amorim's position, with the team having taken four points from four games in the league and been knocked out of the Carabao Cup by League Two Grimsby.

Mirror Football understands that Amorim is losing the confidence of some of his senior players and the next three games will be crucial. United host Chelsea at Old Trafford on Saturday, followed by a trip to Brentford and a home encounter with newly-promoted Sunderland, before the two-week international break.

Should those games not go to plan then United could consider sacking the Portuguese boss in the October international break. Here we take a look at the bookies' favourites for the job and assess their suitability.

The Crystal Palace manager has burnished his reputation recently by turning his side into a supremely organised and efficient machine. He led Palace to the FA Cup in May - an historic achievement which should have led them into the Europa League - and his leadership has been crucial to the side punching above their weight.

The Austrian has worked with a tight-knit squad, getting the best out of them with little rotation. One thing that won't have escaped the United hierarchy is that he plays a very similar tactical system to the one Amorim has been trying to implement. Should they pull the trigger on Amorim, that could ensure a smooth transition, with Glasner - who threatened to resign at Palace over the proposed sale of Marc Guehi to Liverpool - likely to continue with the 3-4-2-1 formation.

However, looking at it in a different way, that could be an issue. One of the biggest concerns about Amorim is how wedded he is to the three-man defence, which means fielding captain Bruno Fernandes in a two-man midfield. Hiring a new boss who subscribes to the same philosophy may not make sense.

The former Manchester United midfielder is available after losing his job at Middlesbrough in June. The 44-year-old was at Boro for two and a half years, but left after they failed to reach the Championship play-offs last season.

Carrick was previously an interim boss at United in between Jose Mourinho's departure and the arrival of Ole Gunnar Solskjaer and served as caretaker after the Norwegian was sacked. Having spent 12 years with the club as a player and most of his years post-retirement at United as a coach, he wouldn't take long to settle at Carrington and Old Trafford. He would be a popular choice among fans.

However, there is no doubt that United represents a significant step up the ladder from Boro and the Championship, with the pressure involved and the need to manage egos a potential question mark for him.

Southgate has been without a job since stepping down as England manager last summer. He is no stranger to being linked with the United job, having been on INEOS' radar before. Sir Jim Ratcliffe is a fan of Southgate's and he was considered before Amorim took over from Erik ten Hag last year.

The 55-year-old won plaudits for his work with England, where he built strong relationships with the players and became a good communicator. Having spent eight years in the Three Lions hot seat, he would command the respect of the United squad.

However, there are bound to be question marks over his long absence from club football, which is a completely different job to that of an international boss. Southgate has only previously managed Middlesbrough - and that ended in 2009. Since then, he has only worked for the FA, first as England under-21s boss and then with the senior squad.

Silva has a wealth of Premier League experience, having led Fulham since 2021 after stints at Everton, Watford and Hull. That longevity puts him third in the Premier League, behind only Pep Guardiola and Mikel Arteta and shows how much his work is valued in west London.

The Portuguese is a pragmatist who bases his sides around structure and organisation and is not afraid to adapt his game plan to suit the opponents. While he may be able to conjure improved results in the short-term at United, there may be doubts over long-term progression.

Silva has worked at mid-table Premier League sides for a significant period now and, although there is an argument which says that is exactly what United have become, INEOS may be wary of an uninspiring appointment.

A left-field proposition, albeit one who has previously been linked with the United job and has admirers inside the club. Pochettino is now the head coach of the United States, who are preparing to host the World Cup next year, so is unlikely to jump ship back to club football in the Premier League.

Pochettino's reputation has taken a dent since his success at Tottenham, with spells at Paris Saint-Germain and Chelsea not working out. He has been under pressure with the USMNT recently and stepping into the glare of Old Trafford may not seem like a good idea for the Argentine.

At his peak, Pochettino's Southampton and Spurs sides were renowned for their high-intensity pressing and front-footed football. While that idea may appeal to United right now, it hasn't been in evidence from a Pochettino team for some time.

5 candidates to replace Ruben Amorim at Man Utd - and biggest concern with each - The Mirror