Carlo Ancelotti has said Juan Bernat will be sidelined for "eight to 12 weeks" after suffering ankle ligament damage last weekend.
Bernat, 24, suffered the injury in the 4-0 International Champions Cup (ICC) defeat to AC Milan and returned to Munich following the game before undergoing surgery on Monday.
Marco Friedl, 19, replaced the Spain international in the 3-2 ICC win over Chelsea in Singapore on Wednesday, while David Alaba was also rested from the game with a minor knock.
However, Ancelotti said Bayern wouldn't be seeking to any replacements in the transfer window.
"We aren't looking for a new left-back," Ancelotti told a news conference ahead of the ICC match against Inter Milan on Thursday in Singapore.
Ancelotti again dismissed speculation regarding Arturo Vidal's future after reports emerged Manchester United were interested in signing the Chile midfielder.
"Vidal is not leaving," he said.