The Costa Rica international scored just twice last season for Martin Jol’s side following his £10.6 million move from FC Twente.
However, the 26-year-old is determined to put his difficult first season in England behind him and has insisted he will show fans at Craven Cottage that he is worth his hefty price tag.
|6/4||Fulham are 6/4 to finish in the top 10 next season with William Hill|
"As a player that plays further up the pitch, it is one of my responsibilities to help in that area," he told the club's official website.
"Whether that is through assists or scoring goals, that's what I am here to do.
"It would be nice to score a few more as the new season progresses though and that's something that I know that I am capable of doing.
"I think there is more to come. I know that the manager has talked about me making a greater contribution and that he has faith that I can.
"Is that pressure? I don't think so. It is exactly what I want to hear because I came to England to show my qualities."