Let's get United's excuses in now: it's very early in the season; one match means almost nothing; the men on the pitch are still getting used to a new tactical system; and there are still a couple of weeks left of the transfer season to get the right players in.
There's no doubt that Rooney can be a hugely effective player for United, but the former Everton striker is notoriously mercurial, his form rising and dipping apparently at random, although it does seem to mirror his fluctuating weight.
The bigger problem, however, is that when things aren’t going according to plan, Rooney has a tendency to drift. Not only to drift out of matches, but from chunks of a season. Rooney’s ability is proportional to his mood, and when the latter is darkened by external factors, there is a further propensity to throw his toys out of the pram, often through contractual machinations using the bargaining chip of his name’s enduring popularity on merchandise.
Don't get me wrong: there was some solid reasoning behind Van Gaal’s decision. Perhaps he felt Rooney’s ennui emanated from a personal fall-out with the previous two coaches; that to give him full trust would bring out the best from English football’s biggest star. Maybe he sensed a growing maturity in Rooney, and that – given responsibility – he could restart the trajectory of development that appears to have plateaued.
The trouble is, that sort of reasoning is a sink-or-swim gamble, relying on Rooney to dig deep into his personal reserves and prove himself one of the best in the world.
And he has shown time and again throughout his career that when asked to sink or swim, he sinks.
When Robin van Persie came to Old Trafford it wasn't just to score goals - it was also supposed to show Rooney an example of dedication and professionalism that would make him up his game, and get the most out of himself in what should be the best years of his career.
What actually happened is that he sulked, and tried to leave.
It's not only United who have fallen foul of his lack of mental strength: England, too, have failed to benefit, with the striker's woeful strike rate in tournament football the major reason for the national side's underperformance in the last decade. If you build your team around a player who consistently underperforms, what else can you expect?
Rooney should have stepped up a level years ago, but instead he's still mistaking passion and commitment for shouting and grimacing. Nobody doubts that the world's best senior players, - Bastian Schweinsteiger to Vincent Kompany to Andrea Pirlo - have passion to burn, but they shows it through their focus, attitude and dedication, setting an example for their team-mates - not by snarling like an angry drunk at kicking-out time.
And leadership, not shouting and snarling, is what United need.
Manchester United have not won a game since Wayne Rooney was made club captain.
— Alexander Netherton (@lxndrnthrtn) August 16, 2014
A joke, of course, but one born out of United's worrying lack of on-pitch leadership and experience in the 2-1 opening day loss to Swansea City.
The departures of Patrice Evra, Nemanja Vidic and Rio Ferdinand – and the retirement of Ryan Giggs – have collectively shorn United of their biggest characters on and off the pitch. Robin van Persie is injured, while Darren Fletcher is still feeling his way back into the game after illness.
During the match with Swansea, the XI on the pitch – which included debutant youngsters Jesse Lingard and Tyler Blackett – seemed lost at times, certainly when they were chasing the game.
Chris Smalling didn’t know whether he was coming or going when United reverted to a back four. He was a little better as part of the defensive trio before that, but only because he knew he was doing neither.
Going forward there was a lack of drive, a collective fear and abdication of responsibility that a senior professional would not have tolerated. The team was crying out for a focus, a rallying point, one man standing tall to radiate confidence and determination to his team-mates, willing them to turn things round and showing them the manner in which to do it.
And all that is simply never going to come from Rooney.
There are other deep-seated problems, of course. Clearly these are early days – we cannot write off an entire season after a poor performance - but it is no secret that Van Gaal wants to bring more players into the club. And ironically, assuming he can manage his way around the dismally inept Ed Woodward, the Dutchman’s hand is strengthened by this setback.
Before the season started I suggested that Manchester United had a chance of winning the league, in part to play Devil’s Advocate, in part down to a belief that Louis van Gaal could turn the clock back to the days under Sir Alex Ferguson. With things looking tighter than ever - Manchester City being quieter than usual so far this window, Chelsea and Arsenal obviously narrowing the gap - my feeling about United emanated from the Van Gaal effect. He would be able to squeeze impressive results from relatively limited resources, as he did with the Netherlands. Pre-season hinted that he would be able to achieve a similar impact with United.
Clearly there were shortfalls in the playing staff. Ander Herrera went some way to filling the gap, but Luke Shaw has thus far been a disastrous acquisition, and the team are still a couple of defenders short of a picnic. The supposed lack of pace is a red herring, although Angel Di Maria would be a welcome addition to their team for a variety of reasons - speed being one.
With the leadership question in mind, however, Van Gaal needs to be particularly careful with his forthcoming acquisitions.
Di Maria is such a good player that he would doubtless have a positive impact regardless of personality – he may not be vocal, but he leads by example, driving his team on in a similar fashion to Giggs.
But in other positions – particularly centre-back and the left side of defence – experienced, dominant characters are required.
Will Van Gaal be able to tempt the right talent? Daley Blind is a decent full-back, and an intelligent man; Marcos Rojo fits the brief in terms of ability, but how is his communication? Arturo Vidal is a world-class talent, but United are desperate for a streetwise centre-half to calm the frayed nerves of Smalling and Phil Jones. Ron Vlaar is probably not good enough, despite his World Cup exploits, although reports are emerging that Mehdi Benatia is keen to leave Roma for a higher level of competition. He would fit United's brief - though on Saturday's evidence, United might not fit Benatia's brief.
Of greatest concern though is Woodward. Can he make any of these deals happen?
So far he has not bought a single senior player from outside the Premier League on the strength of his negotiation skills: The high-profile capture of Ander Herrera was eased by the player's clear-cut buyout clause. And the players Woodward has bought from within English football have been grossly overpriced, with Shaw and Marouane Fellaini looking set to be among the biggest flops in the club's history.
The next two weeks are vital for the club, and for Van Gaal. Despite their lack of European football, United's image has enough credit that they remain a huge draw.
But does Woodward have the nous to exploit that status? And if not, can Van Gaal pull off the deals he needs without him?
Reda Maher – on Twitter @Reda_Maher_LDN
- Sports & Recreation
- Wayne Rooney
- Louis van Gaal