Winger Callum Hudson-Odoi did not make the Bayer 04 Leverkusen team for Sunday's pre-league friendly against FC Copenhagen.
Callum Hudson-Odoi was "a bit ailing," according to Bayer 04 Leverkusen head coach Xabi Alonso.
The winger from Chelsea will be ready again on January 22, 2023, in the German Bundesliga against Borussia Mönchengladbach.
Callum Hudson-Odoi has made nine appearances and assisted one for Bayer Leverkusen in the Germany Bundesliga this season.
He joined the Bundesliga club in August 2022 from Premier League club Chelsea on loan.
He scored his first goal for Bayer Leverkusen in a 2-2 away draw at Atlético Madrid in the UEFA Champions League on 26 October.
The Wandsworth-born winger is likely to move to another club this summer permanently according to reports in Germany.
Bayer 04 Leverkusen will evaluate his performance and make a decision at the end of the season.