Ruud van Nistelrooy looks set for a spell on the sidelines after picking up an injury in Sunday’s win over Xerez.
The former Manchester United man came off the bench to score the final goal in the 5-0 thrashing at the Bernabeu.
It was Van Nistelrooy’s first goal for Madrid since last October after recovering from a serious knee injury.
However, the Dutch striker picked up a thigh injury in scoring and it is feared he could face a month on the sidelines with the blow.
“I got hurt while scoring. I dreamed of this return. I will have an MRI [scan] and hope it isn’t anything serious,” Van Nistelrooy told the club’s official website.
“I worked very hard to return and everything has gone well. Let’s see how my quad is holding up. We aren’t happy with the way we played, but it was a good match. We can improve a lot.”