Vermaelen is yet to feature for Barca since making an estimated €19 million (£15m) switch from Arsenal in August due to the problem, which he picked up while representing Belgium against Russia at the World Cup.
Though he has returned to training numerous times, the club's doctors are yet to clear him to play.
Barca's sporting director Andoni Zubizaretta confirmed Vermaelen is once again undergoing medical tests and was not able to rule out the 29-year-old going under the knife.
"We are in the process of recovery," Zubizaretta said.
"The evaluation will come from the medical services and they will decide what to do.
"We do not know yet if Vermaelen will need surgery, but we must do what is best for him."
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