Head coach Niko Kovac says defender Rafinha has apologised to the Bayern Munich team for his outburst at a lack of playing time for the defending Bundesliga champions.

The Brazilian has started just six league games this season, but Kovac insisted that there was no excuse for the 33-year-old right-back -- out of contract in June -- complaining about not getting "a minute of game time" after sitting out Saturday's 1-0 win over Hertha Berlin.

"Nobody is more important than the team or the club and should not be so critical of the coach," said Kovac on Thursday.

"He has apologised in front of the team, but something like this shouldn't have happened."

Rafinha complaint that "the coach doesn't count on me" comes as Kovac faces mounting personnel problems ahead of Saturday's crunch Bundesliga clash at Borussia Moenchengladbach.

The defending champions start the weekend in second, trailing leaders Borussia Dortmund by three points and face a Gladbach side who inflicted a shock 3-0 defeat on Bayern at the Allianz Arena in October.

However, Bayern could potentially be heading north without some big names, including goalkeeper and captain Manuel Neuer

"(Reserve goalkeeper) Sven Ulreich has trained, Mats Hummels too, Manuel Neuer hasn't, but we hope he can train tomorrow (Friday)," said Kovac.

Bayern are already light on wingers with Arjen Robben and Kingsley Coman out injured, while Franck Ribery and left-back David Alaba are also now sidelined.

"David has a ligament injury, Franck has gastroenteritis, both are definitely out for Saturday," added Kovac.

"(Central midfielder) Leon Goretzka has a few issues with his ankle, whether or not he can play we'll only be able to say tomorrow."

Kovac's Bayern were torn apart by Gladbach's counter-attacks in the clash in Munich, but Dieter Hecking's Gladbach, who sit fourth in the table, crashed to 3-0 defeats against mid-table sides Hertha Berlin and Wolfsburg in recent weeks.

In contrast, Bayern travel with confidence high after winning 10 of their last 11 league games.

"At the moment, we are having a good phase and Borussia aren't, but the results don't necessarily mirror what the current performances are like," said Kovac.

"It will be a tough game and the atmosphere in Gladbach is always great."