Schalke's Marcelo Bordon and Mladen Krstajic have been asked to explain their actions after Saturday's Bundesliga match against Borussia Dortmund.
The German Football Association (DFB) are investigating claims the pair insulted referee Lutz Wagner after a dramatic Ruhr derby which ended 3-3 after Schalke had led 3-0.
Bordon and Krstajic were incensed that Alexander Frei's goal - seemingly scored from an offside position - was allowed to stand, and confronted the official after the match on the way to the dressing room.
Wagner later admitted he had made an error, saying he was "annoyed, because you always want to do your job as well as possible".
He continued: "It was my responsibility as I am in charge, although I could say that it was my linesman's fault."
The DFB, who have already banned Schalke midfielder Fabian Ernst for three games after he was sent off as tempers frayed, could take further action against Bordon and Krstajic.
Both have been ordered to put down their version of events in writing and these will be considered along with Wagner's match report before any action is taken.
Schalke coach Fred Rutten played down his players' protests, saying "football is all about emotions".
Heiko Westermann was also shown a red card by Wagner and, if the DFB now decide to suspend Bordon and Krstajic, it would leave Rutten without four key players for the match against Eintracht Frankfurt on Saturday.