During the first half of the season, Heynckes was able to keep his entire squad happy by rotating week in, week out.
He now appears to have established his first-choice XI, meaning the likes of Arjen Robben and Mario Gomez have had to make do with a place on the bench in recent weeks, but Heynckes is not going to alter his side to satisfy his players' egos.
"For a player not to be happy when they are not playing is quite normal, but that is the case with five or six players," he said.
"This is just the way things are at the moment. I have faith in all of my players.
"The important thing is we talk a lot. It's about honesty and telling the players clearly how you want to act, and there is a good relationship of reciprocal trust with almost all of the squad.
"As things stand, I think everybody in my team is fully fit."
Heynckes is not considering a rotation against Schalke, who have made a poor start to 2013 which culminated in a 2-1 defeat at home to Greuther Furth last weekend.
Nor does Bayern's 5-0 win over the Royal Blues in their mid-season training camp bear any influence on his decision.
"Schalke did not play as badly as people made out against Furth," he said.
"They had a great deal of misfortune in the end, hitting the post and then conceding in stoppage time.
"What I rate the most about Schalke is that they are a good team even when they are unsettled.
"They will come to Munich with a great deal of motivation and they will want to create an upset here.
"We are going to have to prepare accordingly."
Indeed, with a place in Europe next season in jeopardy, Schalke cannot afford to go to the Allianz Arena and hope merely to scrape a point.
"The points are there for the taking and we are going to Munich to give it all we have got," said their coach Jens Keller.
Keller is without striker Klaas Jan Huntelaar, who has an eye infection, while Christian Fuchs is suspended.
"Bayern have a full squad to choose from, but we don't," said Keller.
"But moaning gets you nowhere. Somebody else now has to jump in."