Jadon Sancho is among a group of Borussia Dortmund stars who risk censure over the hiring of a celebrity hairdresser.
The Bundesliga, which is the first of Europe's top five leagues to restart following the interruption to the 2019-20 season caused by the coronavirus pandemic, has established strict guidelines in order to prevent further spread of the illness and protect the health of players and staff.
Players are subjected to regular testing and on the pitch are discouraged from shaking hands with opponents, celebrating goals with hugs or any other non-essential physical contact.
Off the pitch too the league has sought to minimise risks, with the protocol stating that players should not have direct contact to their neighbours, the public and should stay at home and not have visitors.
But six Dortmund players stand accused of breaking those regulations after enlisting the services of star coiffeur Winnie Nana Karkari on Thursday.
Jadon Sancho, Raphael Guerreiro, Manuel Akanji, Thorgan Hazard, Axel Witsel and Dan-Axel Zagadou, according to Bild, received home visits from Karkari in order to cut their hair, and photos released by the German daily shows that neither the players nor the hairdresser engaged in the mandatory use of face masks.
"It is pretty common that our guys must get their hair cut after all these months," Dortmund responded to Bild when questioned over the story.
"But it surely is a no-go, from both sides, to not wear a mask. We will remind our players about that very, very clearly. Also: the stylist should ask himself about his behaviour, too."
Karkari also spoke out over the allegations, insisting that he took his mask off "for the photographs" and "stuck to all hygiene-rules very strictly."
Dortmund have continued their fine pre-lockdown form since German football returned to action, winning three out of four games and scoring 12 goals while only conceding twice.
But Lucien Favre's side came unstuck against Bayern Munich in what may prove an effective title decider, going down 1-0 to Joshua Kimmich's wondergoal to drop seven points behind the leaders; a deficit that with just five games left to play seems insurmountable.