Every week seems to bring a new episode in the Arsène Wenger endgame. Calamitous results, the same old frailties, worn excuses and now it seems a training-ground row with Arsenal’s best player. Alexis Sánchez now looks very likely to leave the club after arguing with Wenger and his team-mates, a disagreement that led at least in part to his omission from the starting XI for the defeat at Liverpool on Saturday.

This development really acts only as confirmation of what even the most amateur of body language experts may have suspected for a while. Sánchez has cut an increasingly irked figure in recent weeks, stalking the pitch and bawling out his colleagues like a man who would much rather be somewhere else. When Wenger is asked about this latest development on Monday, at his press conference for the second leg against Bayern Munich, he may well comment that training-ground arguments happen all the time, which they do, and play down its significance. But when combined with the prevailing mood around the club, recent results and the Chilean’s contract, due to expire in the summer of 2018 and with little apparent enthusiasm from the player for a renewal, this cannot be written off as an isolated incident.

Even if it is the sort of small act of defiance that might frequently happen behind the scenes without entering the public domain, you have to trust that Wenger has the authority to stamp out such truculence and get the player back onside. At this stage, who has that trust? This feels like a man trying to open a door and, finding it uncooperative, attempting to punch a hole in it, such is his keenness to get out.

Sánchez’s relegation to the bench at Anfield on Saturday seemed a curious move at the time, but now at least we have an explanation: not an especially convincing one, though. If Sánchez was left out of the starting XI as a punishment, bringing him on for the second half made it a half-hearted scolding, to say the least. It is a little like sending an errant child to their room but letting them have a burger and a big‑screen TV while they are up there. Either sanction the player by leaving him at home, or swallow his truculence in the knowledge the team are better with him in it. The halfway house just seems like another example of muddled thinking from Wenger, or perhaps weakness: he wanted to punish Sánchez but did not have enough conviction to go without him as an insurance policy.

It is arguably worse if we take Wenger’s explanation at face value: tactics or not, being unable to find a place for his most potent forward among four attacking places verges on the surreal. He can claim that hindsight is 20:20, but that only works if nobody thought it was a stupid idea before the game. Plenty did.

This provides another example of how Wenger staying past his real usefulness is harming the club. There is not a great deal wrong with this Arsenal squad, beyond a little strengthening here and there – a proper defensive midfielder perhaps, or a better left‑back – and you would certainly struggle to argue the squad is significantly inferior to Chelsea’s. Not 13 points inferior, at least. But haemorrhaging talent will not help matters. Another manager may do better, but in potentially alienating someone of Sánchez’s calibre Wenger is now making his successor’s job harder as well as harming his own legacy.

Arsenal are used to losing star players but this feels different. Robin van Persie, Cesc Fàbregas, Patrick Vieira: their departures might not have been absolutely amicable, but they were broadly inspired by a slightly sad realisation they had gone as far as they could with Arsenal, that they had to almost reluctantly leave for the sake of their careers. This time, their top man is seemingly storming out of the club in a cloud of irritation. The great defence of Wenger is that he has not been able to spend money on top talent in order to compete with other, richer teams. Sánchez is the walking example of that no longer being the case, but it is not much use if Wenger cannot keep that talent at the club.

The best Arsenal fans can now realistically hope for is that they get a proper price for Sánchez. Oh, and that he moves somewhere outside England. The alternative would be just too much.