Real Madrid have revealed that Aurelien Tchouameni is set for a spell on the sidelines "with an incomplete stress fracture in the second metatarsal of the left foot".
The France international played the full 90 minutes of Saturday's El Clasico, helping Los Blancos to record a 2-1 victory over Barcelona, with Jude Bellingham netting a brace for Carlo Ancelotti's side.
However, the 23-year-old looked in discomfort at full-time, and it has now been revealed that a foot injury will make him unavailable for selection for an unspecified period of time.
"After the tests carried out on Aurelien Tchouameni by the Real Madrid Medical Services, the player has been diagnosed with an incomplete stress fracture in the second metatarsal of the left foot. His progress is to be monitored," read a statement from the La Liga leaders.
Italian journalist Fabrizio Romano posted on X, formerly known as Twitter, that the midfielder could be out for around six to eight weeks with the issue.
There were question marks over the Frenchman's future at Bernabeu over the summer, having found it difficult to show his best form during the 2022-23 campaign.
A move to the Premier League was thought to be a possibility, with Liverpool, Manchester United and Chelsea believed to be among his admirers.
Meanwhile, a recent report claimed that Arsenal have made Tchouameni their leading midfield target for next summer, with the Gunners keen to pair him with Declan Rice.
The ex-Monaco youngster has been a key player for Real Madrid this season, though, making 14 appearances in all competitions, scoring once.
Tchouameni is now set to miss a number of key matches for Los Blancos in the coming weeks, and he is seemingly facing a battle to play again before the end of the year.
In his absence, Eduardo Camavinga could be used as the deepest of the midfielders, with Toni Kroos and Federico Valverde also playing behind Bellingham.
However, Luka Modric could also take on a more prominent role due to the injury, with the experienced midfielder largely struggling for starts during the 2023-24 campaign.
Real Madrid now have five players on the sidelines, with Thibaut Courtois, Eder Militao, Dani Ceballos and Arda Guler also missing.
However, there is a chance that Guler could be involved in the team's next match, which comes against Rayo Vallecano in the league next weekend.