You occasionally come across some strange sights wandering about on the periphery of the Premier League. Hanging around Chelsea’s training ground a few years ago waiting to interview someone or other I found myself sharing the reception area with a fidgety, florid, shiny-suited man who was pacing up and down and generally looking like he half-expected to be chucked out at any moment. After a few minutes a door opened and the fidgety man leapt up, introduced himself noisily and launched into a chortling, unctuous, doomed attempt to sell a part-share in a private jet to Salomon Kalou.

Of course, he never really stood a chance. I knew it. The fidgety, florid man knew it. And yet somehow the scene still had to play itself out while all three of us sat there, politely, having a really terrible time, Salomon in particular looking touchingly small and delicate and like all he really wanted to do was go for a walk or maybe have a nap or something.

And yet as the minutes ticked by, Salomon and I sharing the odd glazed and baffled look while the florid man rambled on desperately about upgrades and options I felt increasingly that something significant was passing between us. That here perhaps was a moment of shared revelation, a glimpse of the basic existential weirdness of the elite footballing existence, perhaps even a broader vision of the pointlessness of all modern life, the three of us sat there on the edge of the void, burbling about planes. At which point, thankfully, it was all OK again because Didier Drogba walked out and said something and everyone just sort of got up and went away. It was, though, a close one. Thanks Didier!

Perhaps one of the most striking things about Chelsea’s great textural transformation over the last decade is simply the speed with which players and club adapted in the early days, that instant sense of unity around the place in changing times. Looking back it seems clear now that Drogba was a major part of this, a sportsman of such charisma and personality, not to mention extreme psychical splendour, that he could validate even the oddest set of circumstances – including the profound existential claustrophobia of a doomed private jet sales pitch – simply by his grand and glorious presence. With this in mind it was particularly painful to see Drogba clanking about so ineffectually in Wednesday night’s 1-1 home draw with Schalke, his first start since returning to the club. There are, though, mitigating factors. Before Wednesday Drogba had played only 17 minutes of club football since April. “I am a diesel,” he pointed out this week. “I need time to warm up.” But this looked to be a little more than that. The pattern of late-Drogba has been a natural dwindling away of that wonderful, muscular mobility, but against Schalke this seemed to have pretty much bottomed out as he still ran and leapt and chased just at a heart-rending half-speed, continually encircled by that youthful Schalke defence like a medieval siege tower on the verge of being overrun by ewoks.

Didier Drogba shows his frustration during Chelsea’s Champions League draw with Schalke. Photograph: Catherine Ivill/AMA/ Catherine Ivill/AMA/Matthew Ashton/AMA/AMA/Corbis

There was plenty of scepticism at the decision to pay Drogba £3m for his encore year at Stamford Bridge. This has now hardened into a more immediate problem. With Diego Costa troubled by hamstring injuries, Chelsea travel to Manchester City on Sundaywith their striking back-up not just looking thin, but oddly lopsided if Drogba really is the first-choice second choice ahead of the less aristocratic, but quicker and younger Loïc Rémy. Mourinho has always been ruthless, the pragmatist’s pragmatist. But from a distance, this looks like a decision based on sentiment and solipsism, possibly even a simple mistake.

And yet, there is another side to this. For a start it is worth remembering exactly which decelerating 36-year-old centre-forward we’re dealing with here. In his prime Drogba was one of the marvels of the Premier League age, a player of rare and relentless muscular precision who would have improved any team in the world. If he is now a high-mileage diesel engine – a Massey Ferguson, a Talbot Horizon – he remains at bottom a thrillingly high-spec machine.

Plus, there is his broader influence on Mourinho himself, for whom successive champion teams have been pegged out around an imprint of something Drogba-esque, those powerful central runners able to harry and chase and swallow the ball up and make it stick: From Diego Milito at Internazionale to the remodelling of Cristiano Ronaldo into an irresistible central force at Real Madrid, a kind of Drogba-with-nobs-on that for all the fine touches and peerless finishing, retains that same basic driving central force. Costa is a good fit in the role this season. And when Mourinho needed back-up, another semi-Drogba to shadow semi-Drogba No1 he went in the end for the obvious choice: actual Drogba.

How to make it work, though? It seems clear the system Chelsea play now doesn’t suit this less mobile Drogba, who wants to play the game facing his own goal, as Alan Shearer did towards the end, spending his last few seasons basically walking backwards, arms grappling behind him like a man in a blackout searching for the mantelpiece.

Drogba might function better as part of a front two or a compact front three, as he did during the title-winning goal glut under Carlo Ancelotti, or even be reserved for the kind of bespoke direct football bombardment that did for PSG last season. Beyond all that, it is still hard to see him as anything but an asset, to the extent that the quicker they usher him up through the coaching ranks towards the managerial ranks the better. Not simply because he’s a great black African footballer, an intelligent, inspiring man – and somebody, some time, has to break that particular hierarchical stasis. But more simply because he has, for all the occasional theatrics, the odd line crossed, been the best of this Chelsea project; a splendid, tactically vital footballer; and equally vital, a key player in the bare-chested fraternal binds, the strange manly purity of those decisive early years.

They may or may not end up winning another trophy this season. But for Chelsea more rather than less Drogba can only ever really be a good thing.