As Sir Alex Ferguson contemplates his choice to succeed Carlos Queiroz, his assistant manager at Old Trafford, who appears set to take over as the coach of Portugal, the canny Scot will have much to mull over. The appointment of a No 2 at any club is as important as any multimillion-pound signing of a player.

In many respects, the manager’s right-hand man — his sounding board and confidant — is an anonymous figure. Rarely quoted in the media, infrequently asked about team selections or performances, he beavers away quietly in the background. It is how he likes it, mostly. Silence is golden.

Yet his role is invaluable, the bond and trust between manager and assistant is one of the most crucial relationships at a club. The No 2 acts as the link between the players and the management, which includes the chairman and boardroom. He is the buffer, listening to the moans and groans from the players, sifting the wheat from the chaff of information and passing it on to the relevant person.

This may sound as though the assistant is merely a “grass”, a betrayer of secrets. He never says “no” to the boss. The truth is that most players prefer talking to the No 2 in the knowledge that their feelings — perhaps in a diluted, more palatable form — will get back to the manager.

The assistant is spinning plates every day, hoping that only a few crash to the ground. He has to be a juggler, a politician, a social worker, an Agony Uncle and a liaison officer all in one. Yet his financial rewards are usually minute compared with what the players and manager receive.

In my playing days, Frank McLintock was the eyes and ears of John Docherty at Millwall. Frank could be confrontational, but once he had learnt the part, he was fine. Don Howe, the assistant at Chelsea, was pretty good, too. He once took me aside and suggested that I had lapsed into a comfort zone. And he was right.

Nowadays, Pat Rice is the perfect foil for Arsène Wenger at Arsenal. He keeps his head down and gets on with it. Steve Clarke at Chelsea, under José Mourinho, Avram Grant and now Luiz Felipe Scolari, does a similar job at Stamford Bridge. And I can assure you that there is much more to it than doing a spot of coaching and handing out the training bibs.

Ferguson has been well served in the past 22 years by Archie Knox, Brian Kidd, Steve McClaren and Queiroz. Do not forget, either, that it was Queiroz who helped a certain Cristiano Ronaldo, his fellow Portuguese, to settle in at the club and blossom. Ferguson cannot take all the credit.

I have heard that Eric Cantona has been mooted as a potential new No 2 at Old Trafford. I nearly fell off my chair when I heard that. Can you imagine him and Ferguson in the dugout together on match days? Who would be first to punch whom? Cantona is a United legend and should remain that way by staying clear of the role.

Candidates to replace Queiroz

Rene Meulensteen United’s technical skills coach, who has spent the past week overseeing pre-season training with Sir Alex Ferguson. Genuine contender.

Brian McClair Intelligent, highly regarded and loyal servant to Ferguson, but would not bring the same breadth to the role as Carlos Queiroz has.

Paulo Bento A José Mourinho clone, but unlikely to leave first management role at Sporting Lisbon. Likewise Laurent Blanc, the coach at Bordeaux.

Michael Laudrup A talented young coach, who is available after leaving Getafe, the Spanish club, in the summer. He could be tempted by United. What are you waiting for, Sir Alex?

Roberto Mancini Another respected coach looking for work, having left Inter Milan. He is unlikely to accept an offer from United, but you never know.

Pako Ayesterán Former Liverpool assistant manager, but he is primarily a fitness coach.

Words by Oliver Kay