The Belgium international has not featured for Arsenal since the end of August, despite Wenger’s initial prognosis claiming the 25-year-old would be sidelined for two weeks.
“Vermaelen had another setback on Saturday that we are concerned with,” said Wenger. “We are consulting top specialists around the world. Unfortunately I can’t give you any precise date, but I concede that, with this setback from Thomas, we are in a situation where will look around.”
Sebastien Squillaci suffered a hamstring strain during the FA Cup third-round draw against Leeds on Saturday, which could rule him out for the rest of the month.
Reserve team captain Ignasi Miquel, 18, could feature in tonight’s Carling Cup semi-final fist leg at Championship strugglers Ipswich.