Ronaldo, Arbeloa return to Real injured
"Cristiano Ronaldo did not train due to a strain in the adductor muscle of his left thigh, and neither did Arbeloa, who is suffering from a strain in his left hamstring," the club said in a statement on its website.
The club did not indicate whether the players were likely to miss Saturday's La Liga match against Valencia.
Wednesday was the first club training for Real Madrid players back from international duty. Fourteen had played for their national teams, including Ronaldo, 26, who came back injured after scoring two of Portugal's six goals in their 6-2 demolition of Bosnia-Herzegovina in the UEFA EURO 2012 play-off second leg on Tuesday.
Arbeloa, who missed Real's UEFA Champions League match with Lyon earlier this month because of a left thigh injury, played for Spain in their 1-0 loss to England on Saturday and their 2-2 draw with Costa Rica on Tuesday.