The Egypt striker is currently in Germany for a rehabilitation program that could last for up to three weeks.

However, should he remain struggling after the rehab, the 27-year-old could turn to surgery.

“There is a 20% possibility that Zaki may require surgery in Germany. If the rehab worked well there will be no need though,” doctor Al-Monayeri told FilGoal.com.

Zaki remains a major doubt for the Cairo derby clash against Ahli on the New Year’s Eve.

The former Wigan forward has been consistently struggling with injury and fitness problems during the past couple of years.

He was forced to miss Egypt's Confederations Cup campaign last year, as well as the 2010 Africa Cup of Nations in Angola.