Ahly's key left-back Ali Maaloul is doubtful of his appearance in the return match of the African Champions League semi-final against Algeria's ES Setif after picking up a muscular injury in the first leg on Tuesday.
The Tunisian defender was injured in the dying minutes of Ahly's 2-0 home win over Setif in the first test of the prestigious tournament semis. The return match will be played on 23 October in Algeria.
"Maaloul picked up a hamstring injury against Setif. He is in a rehabilitation programme to prepare him for re-joining the trainings normally," Youssef was quoted as saying by Ahly's official website.
The assistant coach did not mention how long the player will remain on the side-lines.
After Tuesday's victory, record eight-time winners Ahly, who are seeking their first Champions League title since 2013, are now in prime position to reach the Champions League final for the second successive year.
Ahly's next match will be in the Egyptian Premier League when they face Ittihad of Alexandria on Sunday.
Ahly are currently 7th on the league table after five games and after having a number of matches postponed due to their participation in the Champions League. The team has collected 11 points, only six behind leaders Zamalek, who have played three more matches.
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