Carle has had an injury-interrupted first season in the Hyundai A-League but was just days away from returning from a broken foot before this latest setback.

The 28-year-old will spend the next month under the supervision of the club's medical staff and receive treatment on his back.

"I just want to be out there with the boys. I am a footballer so not playing hurts," Carle said."We have such a great bunch of blokes here so not to be out there with them week in, week out is really tough.

"I will be positive and stick to the program the club’s staff will set out for me and come back from this."

Sydney head to Melbourne on Friday morning ahead of Saturday night's clash against the Heart at AAMI Park.