Real Madrid manager Carlo Ancelotti has acknowledged that goalkeeper Thibaut Courtois sustained an injury during the 1-1 draw with Atletico Madrid.
Los Blancos went into Sunday's showdown in the capital looking to capitalise on Barcelona's surprise defeat to Osasuna on the previous evening.
Heading into the closing stages, Real were well on course for maximum points courtesy of Eder Militao's goal in the 64 minutes.
However, in the fifth minute of added-on time, substitute Angel Correa netted an equaliser for Atletico, it having the potential to be a pivotal goal for both teams come the end of the season.
Although Real remain in second place in the La Liga standings, Ancelotti's side are still as many as three points behind frontrunners Barcelona.
Courtois suffers injury
There was a point in the second half when Atletico supporters began throwing objects onto the pitch at Civitas Metropolitano, bringing a halt to the game.
Atletico boss Diego Simeone remonstrated with that particular section of the club's support to stop aiming missiles in the direction of Courtois.
The incident occurred shortly after Real had taken the lead, with Courtois celebrating wildly at the opposite end to Militao's goal.
As well as conceding the last-gasp leveller, the night ended on a sour note for the Belgian stopper as he was unable to take any goal or free kicks during the closing stages.
Speaking after the match, Ancelotti revealed that Courtois had sustained a muscle injury and would now be assessed ahead of Real's final two matches before the October international break.
What is left for Real before the international break?
Real face a quick turnaround with a trip to France to square off against Lille in the Champions League next on the schedule on Wednesday.
Three days later, Villarreal are the visitors to the Santiago Bernabeu in La Liga, with Courtois seemingly in a race against time to be fit for either game.
Andriy Lunin is in line to replace Courtois on Wednesday in what would be his first appearance of the season.
