Wayne Rooney's form is foremost among Manchester United's problems

The poor form of Wayne Rooney isn't Manchester United's only problem after three consecutive defeats, but it's the most pertinent one. He is the captain and a club legend and is only three goals away from becoming United's all-time leading scorer with 249 goals.

The 30-year-old has won every major trophy in his 12 years at the club and is popular and respected. Being "a good lad" goes a long way in professional football. Players like Rooney; he's a team man and a joker.

Managers also like him and not only because he's so versatile and prepared to play anywhere for the team. Others might stand their ground and insist on occupying their favoured role but Rooney will just get on with it. It's to his credit that he's been talented enough to play in different positions and that the team comes first, in front of any personal scoring ambitions.

But he's not playing well, something even his most ardent supporters will concede. Rather than fulminating with anger, they're saddened that a once great player is floundering. From being the standout under David Moyes three years ago, Rooney now doesn't look worthy of his place in the team.

There are still moments, such as the one that set up a last-minute winner at Hull last month or a game- changing FA Cup final performance vs. Crystal Palace in May, but it's nowhere near enough.

Rooney continues to start in his usual position behind the leading striker. It is a highly-coveted role: Marcus Rashford, Henrikh Mkhitaryan, Juan Mata and Ander Herrera would all love to play there. Paul Pogba was tried there against Feyenoord, though he didnt impress.

Yet more than one United fan hoped he'd get sent off towards the end of Sunday's game at Watford when he became frustrated at referee Michael Oliver and was booked for a foul on Roberto Pereyra. It could have done him and Jose Mourinho a favour.

Three games out could have offered time for Rooney to refocus, while it also would have taken the decision to keep him in the team out of Mourinho's hands. An absence would also show whether he would be missed or whether there is a better replacement.

He has played worse than he did at Watford, when he started on the right of a midfield three. That, incidentally, seemed to contradict what Mourinho said when he took over, that Rooney was best used as a striker.

But fans are almost unanimous that he should be dropped. In a Monday poll among supporters on United We Stand -- many of whom went to Watford - 92 percent were in favour of that happening.

It's impossible to judge whether Rooney has simply hit a brick wall. In 1997, Eric Cantona called it a day while he was still at the top and just short of his 31st birthday -- the exact age Rooney is now -- and United coaches later said that the Frenchman felt he was on the way down. Meanwhile, Gary Neville realised his time had gone when he was exposed in a game at West Brom in 2011.

Or does Rooney go down the route of Ryan Giggs and change his position completely, play less but still have an influence in games?

There's zero suggestion that he's going to retire but, if Rooney's legs have gone, then it's understandable: He's played 718 games of senior professional football and has put in the hard miles. When Cristiano Ronaldo was making headlines in Manchester, Rooney was doing much of his running.

Through no fault of his own, Rooney has another problem. Initially, he was asked to form a partnership with Zlatan Ibrahimovic, a relationship which would take time even in a stable system, which United don't yet have, unlike Manchester City with Pep Guardiola.

Mourinho's initial idea was for players to get the ball to Ibrahimovic and Rooney, that there was nobody better than the two of them at working the small spaces, but the Swede is disappointed at the lack of service he's receiving. With Anthony Martial also out of form, United have issues up front as well as in the easily overrun midfield behind the forwards.

Luck can play a part in developing partnerships -- Sir Alex Ferguson only hit on the spark between Andy Cole and Dwight Yorke two months into the 1998-99 season -- but an otherwise composed Mourinho blaming referees after each defeat won't wash for long.

We're only seven games in and it's still very early days under the new manager, but it is possible to discern some traits of his United. The big (fame) names start, as do the big (physical) players.

United could have had a much tougher fixture list so far, having only played Man City of the top domestic sides. Coming up are games against champions Leicester City and struggling Stoke, before a six-day spell in which they visit Liverpool and Chelsea. Amid that are League Cup and Europa League games. Will Rooney continue to feature in some, if not all, of those?

Mourinho has been remarkably calm so far. He's been on a charm offensive and a winning start afforded him a honeymoon period. He knew he had to change his image after Real Madrid and his second stint at Chelsea, but on Sunday against a Watford team who'd not beaten United for almost 30 years, he presided over a third straight defeat. The last time that happened to Mourinho was in 2002.

For a man known as a winner, who is as close to a guarantee as there is for organising victories and who United executive vice-chairman Ed Woodward described as "quite simply the best manager in the game today," Mourinho has now lost 14 of his last 32 games in all competitions.

Before that, he'd lost a mere 14 of his previous 105. It's not only Rooney who needs to find his touch again.

Andy Mitten is a freelance writer and the founder and editor of United We Stand. Follow him on Twitter @AndyMitten.