The world of sumo wrestling has been thrown into turmoil after the sport’s biggest star was suspended for apparently faking a doctor’s note and being caught playing football in a Wayne Rooney shirt.

In an unprecedented ruling by the Japan Sumo Association (JSA), the next two championship tournaments — in September and November — will be held without the draw of the undisputedly successful, but persistently scandal-struck, Asashoryu.

Asashoryu (whose real name is Dolgorsuren Dagvadorj) has had numerous brushes with the sumo authorities before. But his latest infraction may be the final straw, say the stable-masters who control the sport.

Despite a life under the constant glare of Japan’s media, the 26-year-old Mongolian champion’s mistake was to forget that the cameras are always running. Several weeks ago Asashoryu announced that he was not fit to take part in an August tournament in Tokyo, and produced a medical certificate attesting to nerve and ligament damage and a fractured back.

Just a few days later, though, he was captured on camera at a charity football event in his native Mongolia — complete with a bright red Wayne Rooney Manchester United shirt. It was not so much his appearance in the match that infuriated JSA officials, but the extraordinary contortions and back-jarring acrobatics that Asashoryu pulled off in his efforts to strike at the goal.

He is now reported to be suffering from post-traumatic stress disorder arising from the JSA’s ruling and has been placed under a form of house arrest within the sumo stable for whom he competes. He has begged to be allowed to travel back to Mongolia, but the JSA and the head of Asashoryu’s stable have resisted.

Sumo insiders believe that part of Asashoryu’s frustration may relate to his famous love of the Tokyo nightlife, and his misery at being confined to the austerity of the stable. He was visited yesterday by a psychiatrist charged with establishing whether one of the greatest sumo wrestlers of the modern era is on the verge of a nervous breakdown. He has been described as undergoing “wild mood swings”, switching suddenly from determination to despair.

Asashoryu has already had to defend his reputation against allegations of match-fixing. With the original medical certificate now firmly in doubt, the JSA’s reaction has deepened the crisis that some sumo veterans believe threatens to marginalise their sport. Last week, seeing the Asahoryu incident as threatening the cultural values of sumo, the Minister for Education joined an appeal for calm.

Despite his relentless ability to win matches Asashoryu has never endeared himself to Japan in the way that other non-Japanese wrestlers, such as the Hawaiian giant Akebono, were able to. Nevertheless, the JSA is aware that it owes much of its current audiences to Asashoryu, whether or not the old elite can stand him or not.