Belgium medical chief Kristof Sas admits there's growing concern about the fitness of Real Madrid attacker Eden Hazard.

Hazard has suffered a fresh injury injury setback at Real Madrid this week. The muscular injury will see the Belgium captain sidelined for a month.

Sas told Nieuwsblad: “We are waiting to know more but it is worrying.

"The injuries of other players like (Dennis) Praet, (Dries) Mertens or (Kevin) De Bruyne at this point do not worry us for the European Championship, it is until a break.

"They can start over, but with Eden it's different. It is a chronic relapse that, in the end, always goes wrong.

"At first it was a problem with the ankle but the last three times it was muscle injuries. Eden is in a vicious cycle and it is not easy to get out. Like any elite athlete, it is necessary for your muscle groups that you train. A soccer player must hit it, turn, jump and everything, at great speed. This is much more difficult during rehab."