Manager Michael Laudrup had revealed earlier this month that the Holland international needed to have an operation and that he expected the 30-year-old to be out for four to five weeks following the procedure.
Swansea had hoped Vorm would be able to play on into January before going under the knife, to allow the club to bring in cover with a minimum of disruption.
But a statement on the club's official website said: "Michel Vorm is set to go under the surgeon's knife today (Thursday) to rectify a long-standing knee problem.
"The Swans had hoped the Dutch keeper would battle through until January, but after suffering more problems against Norwich City last Sunday, it was decided that the injury could not be managed any longer.
"Surgeons will explore the knee before carrying out work on clearing any loose ligaments and fragments of bone, and a diagnosis on the length of time he will be sidelined depends on the scale of the operation."
But midfielder Leon Britton and defender Chico Flores are set to be in contention to face Everton on Sunday after toe and knee problems respectively.
Assistant manager Morten Wieghorst, meanwhile, has played down suggestions Laudrup could succeed Andre Villas-Boas at Tottenham.
The Dane has been mentioned as being among the candidates to take over at White Hart Lane, but former Celtic midfielder Wieghorst told BBC Sport: "I don't think the club should be worried.
"We've seen in his time here he's been linked with a few vacant jobs and he's said: 'I'm staying'."
He added: "Michael has always attracted interest and that's because he's doing a great job [and] because he's a great manager and because of what he's done in the game."