Arsenal loanee Jordi Osei-Tutu is set to be out for four to six weeks due to injury.
The 21-year-old has suffered a hamstring injury and is poised for a spell on the sidelines, as reported by BBC Sport.
Osei-Tutu had got off to a good start at Cardiff, making seven appearances, usually being deployed at right-back.
Last season he had a productive loan spell at VfL Bochum, where he often featured as a right winger and scored five goals.
Osei-Tutu, who joined Arsenal in 2015, has yet to play for the Gunners in a competitive game at first-team level but he has been named on the bench and has featured in friendlies.