The striker joined the Toon on-loan from Leicester City last month.
“He's a good striker and staying on the bench isn't good for the head. Slimani is excellent and will do very good things at Newcastle. He may be a talisman," Madjer told Record.
“[Rafa] Benitez has a lot of experience and will be important on a psychological level. Slimani will solve a big part of Newcastle's problems."