Barcelona attacker Dani Olmo is a major doubt for the Clásico against Real Madrid at the end of the month after sources told ESPN he is likely to be sidelined for up to three weeks.

Olmo, 27, left the Spain squad last week with the problem , missing the World Cup qualifiers against Georgia and Bulgaria , to return to Barcelona for tests.

Barça subsequently confirmed a "muscle injury in Olmo's left calf" on Monday but ruled out any serious damage.

The Catalan club say his "recovery time will be dictated by his progress," with sources telling ESPN he is expected to be sidelined for two to three weeks.

Therefore, he will miss Saturday's LaLiga game against Girona and Olympiacos ' visit in the Champions League next Tuesday.

Barça then travel to the Santiago Bernabéu o

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