The former Watford and Marseille midfielder, who recently established himself in Serie A with Sassuolo, now faces a gruelling four to five months on the sidelines awaiting surgery.
Marsch added: “Ismael is such a great kid. He’s so imperfect but that’s why you love him. He can do great things and the next moment he loses concentration. He embodies a lot of what the team is. It’s a huge loss for us. He’ll be fine, we’ll get him good doctors. He’s got a big future and he’s a big part of everything we’ll do.”