John Giles: Jose Mourinho has signed players he didn't want
There are big games in every season which mark turning points. Tomorrow's match-up between Chelsea and Arsenal is one but this episode is of even greater significance than the points on offer.
Both managers are now firmly in the cross-hairs of public attention and in Jose Mourinho's case, his line-up could well mark the end of an era at Chelsea.
Arsene Wenger's sour trip to Zagreb highlighted a weakness in him which shows no sign of changing. Maybe there is no place at the very top for a civilised man and perhaps he needs a touch of the Gorbals or the back streets of Marseilles in his make-up.
His players respond to what he does and I can only assume that the occasional slump which Arsenal suffer comes from the environment he creates.
In many ways, this is old news but what is happening at Stamford Bridge could be something different, something new.
Before the Champions league game against Maccabi Tel-Aviv, Mourinho told us that he had a 'new dynamic' in mind when he dropped key regulars like John Terry, Branislav Ivanovic and Ramires, men with accumulated service over of almost a quarter of a century at Stamford Bridge, to the bench.
Often, managers will make noises about squad rotation and keeping everything fresh when their real intent is to rest players for a big game ahead.
In the last few seasons, even the Champions League has been used in this way, most notably when Brendan Rodgers left most of his team on the bench for a game against Real Madrid a couple of seasons back.
On this occasion, there is a better than even chance that Mourinho means what he says and that he is moving on or should I say, wants to move on but is hamstrung. That would indeed be momentous.
I've already said this week that I think Mourinho is on the brink and that the only thing keeping him at Stamford Bridge is the fact that he has nowhere else to go but I've thought a bit more about it since he put out the team he picked against Tel-Aviv.
It strikes me now that Mourinho truly believes that key men in his squad who have played for a long time are either over the hill or rapidly approaching that point. Nobody is better placed than he is to make that assessment.
Last year in the summer transfer window we were congratulating Mourinho for some good buys, Cesc Fabregas and Diego Costa in particular and even more so when he turned a squad light on strikers into champions.
Around about January, he would have handed his wishlist to those above him at Stamford Bridge and it is clear from what he has said that John Stones is a player he wants to see at his club so he felt his defence needed more options.
He didn't get Stones but instead, Papy Djilobodji and Michael Hector, a couple of lads nobody has ever heard of from Nantes and Reading. Hector went straight back out on loan to his old club.
I don't believe they were on Mourinho's list and it could be that all the frustration we have seen in him is down to the simple fact that he didn't want to sign these players or Pedro. He said so himself and the same is true of the Petr Cech deal. He didn't want that to happen.
It is hard to assign any other motivation to Mourinho for his keenness to bring Stones in and his decision to drop Terry than his judgement that he needed younger legs.
I believe Mourinho is fighting to make his team as good as it can be and it seems obvious to me that he is meeting resistance to that. I think he looks tortured.
Whether that is because the old guard at Stamford Bridge are so friendly with Abramovich that Mourinho cannot impose what he believes is best for Chelsea I'm not sure.
But for reasons which may become clearer over time, Mourinho is no longer working under the conditions he insists on and I can see only one consequence of that.