The Champions League competitors can book a knockout spot in the competition at Montpellier next week but have fared worse in the Bundesliga in the past weeks after remaining on the heels of leaders Bayern Munich for the first months of the campaign.
Their 3-1 defeat at Hamburg SV on Tuesday, however, saw them drop 13 points behind Bayern in fourth place.
"The team must work harder. They can do it and they also believe they can do it," Schalke sports director Horst Heldt told the club website on Friday. "Fact is we have collected too few points from our last games."
"The players are fully aware that the team is not having a good run at the moment. We want all three points [on Saturday] and we have to have more energy and intensity in our game."
"We have given up a good starting position [in recent weeks] and against Gladbach we want to turn it around."
Coach Huub Stevens will decide later on Friday whether to include Greece defender Kyriakos Papadopoulos, who cut training short with a knee problem on Thursday, and Dutch forward Ibrahim Afellay, fit after an injury break.
"We will have to see if it can work," Stevens told reporters. "It does not have to be a full 90 minutes, they could help out for 30 minutes or 20. But I will have to wait and see if this is possible".
