James Rodriguez will miss the start of the new Bundesliga campaign after the on-loan playmaker picked up a thigh injury against Liverpool.
The Bayern Munich player, who moved to the Germany on a two-season long loan spell from Real Madrid, sustained the problem in his side's 3-0 Audi Cup loss to the Reds on Tuesday.
A statement on Bayern's official site confirmed the prognosis over James' injury, but the German giants failed to put a definitive timeframe on his return to the first-team picture.
The statement read: "FC Bayern will have to make do without new signing James Rodríguez in the coming weeks.
"A thorough examination by FC Bayern's medical unit revealed that the Columbian sustained a muscle injury to his right thigh in the 3-0 Audi Cup semi-final defeat to Liverpool."
James completed a shock temporary switch to the Allianz Arena on 12th July after plenty of speculation about his Bernabeu future.
The 26-year-old Colombia international had been linked with either a move to the Premier League or a transfer to Paris Saint-Germain, but he surprised fans and the media alike by hooking up with former Real boss Carlo Ancelotti at the reigning German top flight champions.
Meanwhile, Bayern also confirmed that two of their other senior stars had sustained injuries in the semi-final defeat to Jurgen Klopp's men on home soil.
Thiago Alcantara and David Alaba were also withdrawn from the fray at varying points of the match, and Die Bayern's statement continued by revealing the extent of the issues picked up by the midfielder and full-back.
It added: "Thiago Alcántara will miss the Supercup final against Borussia Dortmund on Saturday with an abdominal muscle injury.
"David Alaba, who had to be subbed off against Liverpool as well, received treatment on Wednesday and will train individually on Thursday."
Bayern will take on rivals Borussia Dortmund at the weekend before they kick their 2017/18 campaign properly with a DfB Pokal Cup first round tie against lowly Chemnitzer FC.