What happened to José Mourinho? He was always arrogant and crass, but at least he was entertaining. He hasn’t always produced teams that were enjoyable to watch, but at least he won things. Whatever entertainment value he had disappeared somewhere in Madrid, and even though this season is still in its infancy, he doesn’t look like winning much this year, either. He’s lost the charm, doubled down on the abrasiveness, and his team’s form is a raging dumpster fire.

Mourinho has spent the season so far having a go at his own staff, having a go at other managers, having a go at referees, and having a go at the media. Worst of all, he’s even banned soccer’s most sacred institution: banter. Truly, the man has gone too far. It’s bad enough that he’s been grumpy and defensive, and that his team has been awful to watch this season, but now he’s gone and banned the #bantz. José Mourinho: Patron Saint of Joylessness.

Across Mourinho’s two stints in the Premier League, his favorite opponent has been Arsène Wenger. Mourinho’s first arrival as Chelsea manager coincided with the start of Arsenal’s decline as a serious force in England’s top flight. Both teams have been ever-presents in the league’s top four in the ensuing decade, but only Chelsea has actually won the thing. Arsenal has, for the most part, been treading the waters of mediocrity – a fact that Mourinho has been all too happy to raise again and again.

Mourinho obviously enjoys taking the piss out of Wenger and has never needed much prompting to resort to insults, calling him a “voyeur,” and “a specialist in failure.” And whenever Mourinho is asked about being under pressure, making thinly-veiled references to Wenger’s long title drought is a favorite defense mechanism. For almost all of Mourinho’s combined six or so seasons in England, Wenger has been his punching bag, both on the field and off.

Arsenal versus Chelsea is nominally a “big” game, but it has hardly been a contest in the Mourinho-era. In fact, Wenger has never even beaten Mourinho in a competitive match. That said, Wenger did triumph over his rival for the first time ever in this season’s Community Shield (a game that is essentially a glorified friendly, unless your team wins it).

SEE MORE: Mourinho dismisses Gerrard’s claims of a rift with Terry.

For Saturday’s match at Stamford Bridge, Mourinho will be leading a team that looks as vulnerable as any he has ever coached. Chelsea may have wiped the floor with Maccabi Tel Aviv   midweek, but that can be safely chalked up to 1.) Maccabi Tel Aviv not being very good, and 2.) Karma for the shameful anti-immigrant stance of certain match-going Tel Aviv fans. Arsenal, despite being, you know, Arsenal, will present a much stiffer challenge for the Blues.

Chelsea’s form in the league so far has been nothing short of disastrous. Mourinho is failing to get the most of his players, which is not only a fireable offense at an elite club but also precisely the opposite of what he built past success on. If Mourinho fails to sufficiently motivate his charges for a game that they should feel entitled to win, his job will suddenly be a lot less secure. Arsenal, on current form, don’t exactly constitute an irresistible force, but Wenger’s men should be emboldened by their preseason win and further encouraged by Chelsea’s weakened state. Wenger is too experienced to get carried away by a solitary league game in September, but he would love to play a pivotal role in getting his longtime tormentor the sack.

In most scenarios, much of this kind of speculation would be considered knee-jerk and premature. But this is not most scenarios. This is Jose Mourinho — one of the most volatile and divisive figures in the game — and Roman Abramovich – an owner who has never had a manager he wasn’t afraid to sack, severance pay be damned. Yes, Mourinho is only just into the third year of a recently extended contract, and yes, he is still the reigning Premier League champion. It is always sensible to apply some perspective, and it would be churlish to ignore Mourinho’s history.

SEE MORE: Premier League clubs still failing Europe’s tactics tests.

Let’s not forget that Mourinho’s last stint in Chelsea ended in extreme acrimony, with the Portuguese getting his walking papers before the first snow had fallen after just three and a bit seasons at the helm. His most recent job at Real Madrid ended with even more bad blood on both sides after he had fallen out with players, his superiors, and the local media.

Sound familiar? If history is to be our guide, Mourinho may well be heading for another nasty breakup, except with less of the preceding success that is supposed to make it all worthwhile. Maybe he’s just not that special anymore.