Hoffenheim coach Ralf Rangnick claims two of his players reported late for a statutory doping test after their 1-1 draw with Borussia Monchengladbach earlier this month because they were changing their shirts.
Monchengladbach have lodged an official appeal after it emerged Andreas Ibertsberger and Christoph Janker were both 10 minutes late for the test and the German FA (DFB) are investigating the matter.
Although the results of the tests were negative, the players still face the prospect of a suspension.
Hoffenheim could also be fined while the match may be awarded to Gladbach.
Rangnick, though, explained why the pair were late, telling SWR TV programme Sport im Dritten: ''In the past, even the anti-doping expert said it was fine for players to go into the dressing room briefly to put on a fresh shirt.''
Rangnick denied a post-match debrief was to blame, adding: ''It is definitely not true that I called a team meeting. I didn't know that day which players had been picked for the test.''
Gladbach, though, have already confirmed their intention to appeal.
''To preserve any possible claim that could emerge from the breaching of doping rules, Borussia have today lodged an appeal within the given deadline,'' Gladbach said in a statement.
Gladbach's decision to appeal has been ridiculed by their Bundesliga rivals.
Bayer Leverkusen director of sport Rudi Voller described it as ''a joke'', while former Gladbach midfielder Stefan Effenberg told Premiere television he was ''ashamed'' by his former side's attitude.
The German FA have asked Ibertsberger and Janker to provide written statements explaining their actions.
A similar case in Italy recently saw two players suspended for a year. Daniele Mannini of Napoli and Davide Possanzini of Brescia were both 15 minutes late for a doping test and were later banned by the Court of Arbitration for Sport.
However, Brescia escaped any punishment.