Bayern Munich are facing the prospect of battling for both the league title and the Champions League without key players Dayot Upamecano and Alphonso Davies, who returned from international duty injured, the German giants said Wednesday.

Canadian international Davies, 24, a key presence in midfield for Bayern, tore the ACL in his right knee during their 2-1 win over the United States on Sunday in the CONCACAF Nations League.

Bayern said he will definitely be out for the rest of the season, and could be sidelined for six months.

Defender Upamecano meanwhile will be out for "several weeks" after suffering a left knee injury during France's 2-0 win against Croatia in the Nations League quarter-finals on Sunday.

Despite the injury the 26-year-old scored the decisive penalty in the shoot-out -- the match finished 2-2 on aggregate -- to take them through to the semi-finals and a meeting with European champions Spain.

"Unfortunately, there's always the risk of players returning from international breaks with injuries -- this time we've been hit particularly hard," Bayern board member for sport Max Eberl told the club website.

"The absence of Alphonso Davies and Dayot Upamecano weighs heavily on FC Bayern.

"We have a strong squad and will compensate for these absences.

"We'll now grow even closer together. The quality is there to continue pursuing our big goals."

Bayern are six points head of Bayer Leverkusen in the Bundesliga -- with eight matches remaining -- and face Inter Milan in the quarter-finals of the Champions League.