The 24-year-old Spain international joins the Cottagers on a one-year loan deal, having made 170 appearances at senior level for his hometown club.
Fulham have completed the capture of Sevilla goalkeeper Sergio Rico on a one-year loan deal that will keep him at Craven Cottage until the end of the 2018-19 season.
The 24-year-old, a Spain international, has made 170 senior appearances for his hometown team, and won the Europa League in his first full professional campaign, in 2015.
He joins the Cottagers as they return to the Premier League following last season’s Championship play-off final win against Aston Villa.