A win for Villa at Carrow Road on Saturday would all but end their relegation concerns and move them ahead of the Canaries in the table but boss Paul Lambert may be without Clark and El Ahmadi for the tie against his former club.
Both players missed the 6-1 win over Sunderland as Clark has a foot injury and El Ahmadi has a groin problem but Lambert is hopeful the pair will both be fit for the trip to Norwich.
"Ciaran hurt his foot in training the other day. Karim got a groin strain the other day, too. It was too risky to play them," Lambert told the club's official website. "We will see how they are later in the week."