Ruiz joins PSV on loan
The Costa Rica international has fallen down the pecking order at Craven Cottage since Rene Meulensteen was placed in charge in December, featuring in just two matches under the Dutchman.
He will Costa Rica at the World Cup, where Jorge Luis Pinto's side will come up against England, but it remains to be seen if he will return to Fulham next season.
The move to PSV had been expected and the club issued a short statement on their website to confirm the deal had been completed.
"The club can confirm that Bryan Ruiz has joined Dutch outfit PSV Eindhoven on a loan deal until the end of the season," it read.
"Having made 14 appearances for the Whites in the current campaign, Ruiz will now link up with Phillip Cocu's side as they aim to improve on their current standing of seventh in the Eredivisie.
"Everyone at Fulham would like to wish the Costa Rica captain well during his temporary spell in the Netherlands."
Ruiz sees the move to Eindhoven as a chance to regain some form ahead of this summer's World Cup finals.
"When the opportunity arose I was interested," he told PSV's official website.
"It's true I didn't have much playing time at Fulham lately, so I see this as a great opportunity for me. I want to get my confidence back, help PSV finish as high as possible and prepare for the World Cup."
The striker also assured PSV fans that he is committed to his new club, despite his previous success with Eredivisie rivals Twente.
He said: "I'm very motivated. I'm going to do my best for PSV.
"I remember every game I played against PSV was an exciting battle, but now I'm in the other dressing room and I will give everything for PSV.
"I have fond memories of my time at FC Twente but I am a professional and will put 100 per cent into PSV to achieve what we want to achieve."