The Belgium international has yet to make a competitive appearance for the Catalan club since joining from Arsenal in August for a reported €19 million, having signed while still recovering from a hamstring problem sustained at the World Cup.
Vermaelen was declared fit to return to action at the tail end of September but his comeback was postponed for a further two months before he was finally given the all-clear to make his debut in Tuesday's Champions League clash with APOEL.
However, the versatile centre-half pulled up in training with a recurrence of his hamstring problem and it has now been announced that the 29-year-old requires an operation that could even end his season.
"Thomas Vermaelen will undergo surgery on his right semitendinosus muscle by doctor Sakari Orava next Tuesday in Finland," read a club statement released on Thursday evening. "The estimated recovery time is four to six months."
Vermaelen has been plagued by muscular problems in recent seasons and had lost his place in the Arsenal starting line-up before departing for Catalunya during the summer.