Who will be the heir to Sir Alex's throne?

After their controversial loss to Real Madrid in the Champions League, Sir Alex was lost for words. He couldn't even do his post match interview. This didn't seem like such a big loss to arguably the best club in the world (though not according to La Liga), but is there some deeper meaning; perhaps that was Sir Alex's last Champo match? If he does go, here are my five most likely managers to replace him at Old Trafford:

1. Jose Mourinho

Jose was very respectful after his team's victory on Tuesday. Could it be because he does want to offend his future supporters (unlike Rafa)? He is the most likely successor  after all, he has said he wants his next managerial job to be in England. Also, he is not enjoying his life at Real, despite recent defeats of arch-rivals Barca, meaning he will be open to a move away from 'los galacticos'. 

2. David Moyes

It seems fellow Scot, Moyes had been hand-picked by Fergie to replace him eons ago. Since then Moyes has done exceptionally well with limited resources at Everton, achieving European qualification and managing to finish ahead of the red team from across Stanley Park last season. However, Moyes is committed to the Toffees' cause and may not want to leave, although many would like to see what he can do with the right support and money.

3. Pep Guardiola

Guardiola was a front runner for the Chelsea job this season, but he went to Bayern instead. This is the same problem with him joining United, if he were, it would have to be in three seasons when his Munich time is up. However, he is a great manager; he plays the right way and can get the most out of his squad. This could entice the owners to pay compensation in order to get him in, which could win over the fans support.

4. Michael Laudrup

Laudrup has just signed a contract keeping him at Swansea until 2015, which could hinder him joining any bigger clubs, like United, who are certain to want him after what he has done this season with an average Swansea team. He is clearly a good manager, who gets on well with his players and supporters, so he could fulfill the needs of United.

5. Ryan Giggs!

Despite just signing a one year deal to play some more, he could be enticed to hang up his boots and take up the managerial role at his adopted home. The players would love him, Sir Alex would advise him from the wings and he would be backed by the board. However, it is a big risk hiring someone who has never managed before in order to try and win the most hotly contested league in Europe, and he may want a break with his family before putting his whole life on the line again.

There are certainly some top quality managers waiting in the wings should Fergie retire, but ultimately, that could be in another few years and until then, we will just have to wait and see if any more managers put themselves in position to take over from the great man.