Whites head coach Marcelo Bielsa revealed on Monday morning that Klich had been granted early leave ahead of his bid to represent his country this summer.
Sousa then named his squad on Monday lunchtime.
Bielsa said: "Klich is not injured. The evolutions that I make over the campaign are for the needs of each player and in the case of Klich the decision I made I think was the most favourable one for him."
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Thank you Laura Collins