Bundesliga leaders Bayern Munich have to tremble for the three points after the substitution in the 4-1 win over SC Freiburg.
The people of Breisgau filed an objection to the rating of the game on Monday shortly before the deadline, and the sports court of the German Football Association (DFB) must now decide on the possible consequences.
However, the chances of success of the protest are uncertain.
Even experts disagree on the applicable regulations, both the pure application of the football rules of the DFB and the use of the legal and procedural rules of the association would be possible.
The decisive factor would probably be the assessment of the sports court as to whether Coman, as the twelfth man on the field at this moment, is considered a player who is not eligible to play or be used.
The Frenchman didn't leave the field in time for a double substitution in the 86th minute, so the Munich team played with one man for 16 seconds.
Even with a point deduction, the record champions in the table would still have a six-point lead over the closest pursuer, Borussia Dortmund.
If the points were awarded, Freiburg would catch up to RB Leipzig in fourth place in the Champions League.