The 21-year-old has risen through the ranks of the La Liga side and has made 48 appearances for their first team since his full debut in 2014. Prior to that he played 35 times for Espanyol B.
Lopez has also been capped at Under-21 level by Spain and was named in the senior squad for a friendly against Bosnia and Herzegovina earlier this year.
He is also a familiar figure to Mauricio Pochettino from the manager’s time in Barcelona.
Lopez will wear the number 30 shirt.
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