Key Atletico star Diego Costa is struggling for fitness with a hamstring injury and could miss the clash with Arsenal in the Europa League semifinals.

The striker suffered the injury as Atletico suffered defeat to Sporting on the night but would go through to the semi-finals thanks to the first leg victory.

Costa suffered a hamstring injury, but the club is not putting a timeframe on the striker’s recovery.

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In a statement on the club’s website, Atletico said:

After undergoing medical exams this Friday, April 13, he has been diagnosed with a hamstring injury to his left leg.

Costa would be a big miss for the Spanish giants but would help Arsenal’s Europa League chances massively.

The former Chelsea striker will at least miss the clash with Levante, but will also be a doubt for the games against Real Sociedad and Real Betis.

Arsenal will hope Costa does not return in time for the game on the 26th April, with the first leg being played at the Emirates Stadium.