Eden Hazard's injury woes at Real Madrid look set to continue after the Belgian pulled out of the squad to face Real Valladolid in La Liga on Wednesday with a muscle problem.
Hazard was due to make his first appearance of the season but instead is expected to be out for at least two weeks, raising doubts around his availability for the Clasico against Barcelona in October.
"After the tests carried out today on our player Eden Hazard by Real Madrid Medical Services, he has been diagnosed with a muscle injury in his right leg," a club statement confirmed.
Earlier on Wednesday, Belgium coach Roberto Martinez had called up Hazard to his squad ahead of Nations League games against Iceland and England next month, as well as a friendly against Ivory Coast.
But Hazard is likely to pull out following his latest setback.
"If Eden is on the pitch with Real Madrid, it is because he is 100 percent (fit) and he will then join the Red Devils," Martinez had said.
"We are not going to use him at 99 percent and Real won't either for the same reasons. If he is not on the pitch tonight and Sunday, he will not come and will continue to train with Real Madrid."
Hazard has missed Madrid's opening two matches in La Liga, with coach Zinedine Zidane adamant the 29-year-old would only play when he was ready.
Asked earlier this month if Hazard had recovered from the ankle injury that plagued him last season, Zidane said: "I don't know, I can't tell you exactly.
"He is better and the most important thing is him, his feeling, that he is 100 per cent. We have time, we are starting the season. What he needs is to be 100 or 120 per cent."
Zidane's caution came after a nightmare opening year for the forward who, after joining from Chelsea for 100 million euros ($113m), suffered a thigh strain the day before his first game.
On his return, he showed glimpses of his best form, only to break a bone in his right ankle in November, which then required surgery in January and kept him out until February.
But Hazard was not completely healed when he came back and was in and out of the team during the run-in, starting only five of Madrid's 11 games after the league resumed in June.
After Valladolid on Wednesday, Zidane's team play away at Levante on Sunday ahead of the international break.
Madrid are then scheduled to face Cadiz at home on October 18 before the first Clasico of the season against Barcelona a week later at the Camp Nou.