Real Madrid captain Sergio Ramos is a fitness concern ahead of Saturday's Clasico against Barcelona at the Camp Nou.
Ramos was substituted at half-time in Spain's friendly draw with Italy last week with a reported back problem, and missed Sunday's goalless draw in Romania.
He sat out Monday's Madrid training session and was unable to take a full part in Tuesday's runout.
The news was included in a club statement on Madrid's official website.
"The team completed the second training session of the week at the Real Madrid City," the statement said.
"They continue to prepare for the match against Barcelona on Saturday. Sergio Ramos completed the first part of the session with the group before continuing to work indoors."
Other returning internationals Nacho Fernandez, Isco, Luka Modric and Mateo Kovacic were given Monday off by Blancos coach Zinedine Zidane, but returned to full training the following day.
Gareth Bale and Karim Benzema have been working with Zidane during the international break, having not joined up with Wales or France.
Barca go into Saturday's game with a 10-point advantage over third-placed Madrid in La Liga, with eight games remaining.
Both they and Madrid have Champions League quarterfinal commitments the following week, with Barca at home to Atletico Madrid on April 5 and Madrid away to Wolfsburg on the following day.