The Egyptian star made his Dortmund debut in the 1-1 draw with Bayern Munich on Saturday and was substituted midway through the second period.

"He still lacks harmony with his teammates," Klopp was quoted as saying by the club website.

Klopp, who was Zidan's coach at Mainz, said that the international forward hasn't trained enough with the rest of players and he couldn't show what he can do against Bayern.

"But he will deliver, he has a lot to add to this team," Klopp added.