Ahly defender Mahmoud Metwalli picked up a partial tear in a knee ligament during Monday's 3-0 league win over Aswan and will be off the field for an undetermined period, the Cairo giants announced on Tuesday.
The 27-year-old player left the match in tears at the 23 minute-mark, leaving Swiss coach Rene Weiler confused ahead of Saturday's anticipated Cairo derby against archrivals Zamalek.
"Scans revealed that Metwalli is suffering from a partial tear in his anterior cruciate ligament (ACL). The head of the club's medical committee is yet to examine the player to determine the rehabilitation programme and how long it will take," Ahly's football director Sayed Abdelhafiz was quoted as saying by the club's official website.
Since joining Ahly last summer from Ismaily, Metwalli, who is on a five-year contract, has established himself as one of the key elements of the team.
He has made 15 appearances with Ahly in different competitions so far this season.
The victory over Aswan extends Ahly's unbeaten run this season, giving them their 18th victory in 20 games.
The champions currently top the league table with 56 points, 18 ahead of second-placed Zamalek, who still have one match in hand.
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