The striker, who has 33 international caps, was at the Reebok Stadium to watch his new team-mates draw 0-0 with West Brom.
The 27-year-old signed for the Spanish club from German side Borussia Dortmund last summer.
He began his career in Holland with Feyenoord, before spending two seasons in Germany with the Bundesliga giants.
After a £4m switch to the Spaniards, he struggled to replicate his previous goalscoring form, despite being a first-team regular for a side which qualified for the Uefa Cup with a 6th place finish.
“It will take a little bit of time for him to acclimatise because it is entirely different to any football he will have seen,” he said.
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