Jadon Sancho and other Borussia Dortmund players have come under fire from the Bundesliga club over having haircuts at home and appearing to violate hygiene rules.
Photos on social media showed them and the hairdresser without face masks.
Sports Director Michael Zorc said on Thursday it appeared that the players and the hairdresser observed all rules during the cut itself.
Zorc said: “However, taking off the masks for the photo violated the rules.
“We were in contact with the German Football League (DFL) which says in the hygiene concept that allowed the Bundesliga restart that players must have no contact to the outside world at home and cannot receive visitors.
“We talked to the players again in a very clear way and made it very clear to them how they should behave.
“We also talked to the hairdresser. I don’t understand why you have to take pictures as well.”
Zorc confirmed that young star forward Sancho was among the players but also said: “We shouldn’t forget that Jadon is 19 and testing his limits.”
Second-placed Borussia Dortmund host Hertha Berlin on Saturday without suspended defender Mats Hummels, while teenage striker Erling Braut Haaland will be a late decision following injury.