"Miki Roque had been fighting pelvic cancer since March 2011," the La Liga club said in a statement on their website.
"The board of directors, the technical staff, the first team and the youth ranks, as well as the most important section of the club, the fans, are united in the tremendous pain felt at the passing of a young footballer, of one of our own."
Roque's death prompted an avalanche of tributes on Twitter, including from several Spain internationals competing at Euro 2012.
"A big hug for Miki Roque's family," central defender Gerard Pique wrote. "I knew him when he played for Liverpool and I was at [Manchester] United. Rest in peace friend."
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