Pressure is mounting on the Royal Blues' coach with five points currently separating them from fourth place and qualification for the Champions League next season.
Furthermore, they have already been knocked out of the DFB-Pokal and face a challenge to reach the quarter-finals of the Champions League after being drawn against Real Madrid in the last 16.
Schalke's director of sport Horst Heldt has admitted the coach's position is hanging in the balance, and that a decision one way or the other can be expected this weekend.
"We live in a performance society and we've made ourselves open to attack by not obtaining the desired results," he said in the Bild newspaper.
"Speculation is therefore inevitable.
"I don't want to give any false promises or lies, but I'd rather just be respectful with everybody.
"We're sticking to the plan, which is to make an analysis on Sunday after the Nuremberg game.
"Every single player will be examined, and that includes the coaching team too. It will all come down to how we summarise the first half of the season."
Roughly translated, Heldt's words indicate that Keller is dependent on how his side performs at the Frankenstadion, whereas the result rather than the actual performance is the priority.
The under-fire coach seems to have understood that, making his one wish for the festive season "three points in Nuremberg".
"We want to end the year on a high and that means we'll put all we can into getting the three points," he added at a press conference.
Getting three points in a single game has remained elusive to Nuremberg so far this season, so there are no prizes for guessing what their aim will be on Saturday.
"We want to win the game," said coach Gertjan Verbeek. "I'm convinced that the first game we win will open the floodgates."
Verbeek is without the suspended Emanuel Pogatetz, but Verbeek says there will be "no other change" to the team he sent out against Hannover a week ago.
There may be a change to the squad this winter, though, with the Dutch coach revealing his interest in signing defender Jan Kirchhoff from Bayern Munich.
"Everybody knows we need a player for this position and one of the names we've looked at is him," said Verbeek.