By Pat Nevin Former Chelsea and Scotland star

Chelsea's perceived problems and growing speculation that manager Jose Mourinho will walk away at the end of the season are a source of concern for every one of us who wants the club to do well.

Those of us with Chelsea at heart have waited a long time for the success they have enjoyed and we don't want to see it jeopardised.

In the long-term, Abramovich's money is more important than the manager - but it doesn't guarantee the success Mourinho has had Pat Nevin on Chelsea's big question

As a Chelsea person, I am not trying to gloss over this in a Chelsea way because there are obviously problems - and no-one can deny that.

Chelsea need to bring in reinforcements in the transfer window - that is an absolute stick-on. If striker Didier Drogba gets injured they will not win the Premiership or the Champions League.

We will look at the potential problem areas and how much Mourinho means to Chelsea, plus the impact of any possible departure, later, but first we should also add a dose of reality to the debate.

Mourinho may be miffed that not everything is going his way but he isn't walking anywhere yet and Chelsea are still in contention for four major trophies.

They have lost their two key defensive figures in goalkeeper Petr Cech and John Terry but if they get them back and can build on the win against Wigan with three points at Liverpool on Saturday, I happen to think they will be in a fantastic position.

Obviously the opposite is also true - if Manchester United pull away and Chelsea slip in the Champions League, then the stories of turmoil will probably rumble on.

It is clear, however, that this is the most difficult period since Mourinho arrived and in any big, complicated business that is fuelled by high finance, there will be a reaction.

All Chelsea fans will hope any differences will be put aside - and any supporter who is not in the inner sanctum is wondering whether all the stories of unrest and rumours of a breakdown in the relationship between Mourinho and owner Roman Abramovich are true.

Striker Andriy Shevchenko's position is the subject of much debate.

If he was not bought by Mourinho then that is a concern.

Some might say Mourinho could have blocked the deal if he didn't want to buy him but my guess is that as a manager he could say: "Buy whoever you want because it's your club - but I don't have to play him."

I think this is the case at other clubs but Shevchenko's case is more subtle because he was expected to play - given his outstanding record and ability - and expected to do well.

The situation has been complicated by Shevchenko's struggle for top form.

If Mourinho did leave, I think it would be a devastating day for Chelsea.

One of the questions that has been asked is - what is more important, Mourinho's management or Abramovich's money?

Jose Mourinho is the best manager Chelsea have ever had - it would be a devastating day if he left Pat Nevin on 'The Special One'

In the long-term, it is the money, which is a painful thing for me to say because Mourinho is the best manager the club has ever had.

If Mourinho left it would take a lot of time to turn it around again and there would be a lot of rebuilding to do.

People say it is easy for managers to go out and spend money, getting all the world's best players in the process - but if I wanted to produce 'Exhibit A' for the case against this, I would give you Real Madrid.

Some of the game's greatest coaches have gone to The Bernabeu, spent lots of money on the world's best players and how is their trophy cabinet looking right now?

I am huge admirer of Mourinho. I interviewed him and his grasp of tactics and technique was quite stunning. I could happily listen to him for three hours just talking about these subjects.

The recent match between Everton and Chelsea was a classic example of Mourinho at the top of his game.

Every year there seems to be a tactical battle between David Moyes and Mourinho, which Mourinho just sneaks, maybe because he has a better group of players.

But some of the adaptations he made to get three points and win 3-2 were fantastic. It was the work of a great coach.

He needed brilliance from Drogba and Frank Lampard at Goodison but his tactics also played their part.

Mourinho is an outstanding man-manager as well.

He has perfected the art of getting a lot of people earning a lot of money to remain very hungry. There might have been a bit of a wobble with that recently but he has done it over an extended period at Stamford Bridge.

That is not as easy as people may think but he has done it. He keeps players hungry and the ones that are not are moved on quickly.

This is a difficult skill but Mourinho can do it and knows the players he can do it with.

As someone who works in the media, I realise there is no smoke without fire but, equally, Mourinho isn't walking anywhere yet and there has to be some perspective.

If they get Cech and Terry fit, and in the meantime get a result at Liverpool, then maybe some of the speculation will fade.

One thing is for certain, if Mourinho left it would be a dark day for Chelsea.