Playmaker Sergio Canales is out of Real Madrid CF's UEFA Champions League trip to AJ Auxerre on 28 September with an ankle injury that makes him a doubt for Spain's UEFA European Under-21 Championship play-off with Croatia.

A late substitute in the 2-0 opening Group G defeat of AFC Ajax, the 19-year-old sprained ligaments in his right ankle during training on Sunday and has been ruled out for up to three weeks.

The summer signing from Real Racing Club will also struggle to return in time for the two-legged U21 qualifying decider against Croatia on 9 and 12 October.

A 2008 UEFA European U17 Championship winner and U19 runner-up in July, Canales made his first two U21 qualifying appearances earlier this month, scoring in the victories against the Netherlands and Poland.