Kingsley Schindler, who started in the 2-0 loss to VfL Wolfsburg, has to take a break from training.
The winger missed the start of training this week's Tuesday because of an illness, according to FC Köln.
Over the course of the week, it will become clear which personnel head coach Steffen Baumgart can plan with for the clash with Union Berlin on Saturday afternoon. Perhaps Baumgart will again hand out some starting eleven guarantees at the match day press conference.
In January 2019, it was announced that Schindler would leave Kiel after the season and sign a contract until 2023 with FC Köln who achieved promotion to the Bundesliga later that season.
In August 2020, Schindler was loaned to Hannover 96 for one year. He returned to FC Köln after the loan deal expired.
Kingsley Schindler has made 19 appearances in the German top flight this season.