Vermaelen sidelined with calf strain
The Gunners were already missing four defenders when the Belgian international deepened the club's injury woes by limping off during the 1-0 win over London rivals Queens Park Rangers in the Premier League.
"We have lost Vermaelen for two or three weeks so I have to look if I can find somebody on loan," said Wenger.
Vermaelen is normally a central defender but has played as a left-back recently to cover for Kieran Gibbs and Andre Santos who have been sidelined with groin and ankle injuries respectively.
"It would be stupid for us to drop points because we don't have a left back," Wenger said after Arsenal climbed to fourth in the table.
"We now have three left-backs out. Francis Coquelin came on in this position and did quite well but he is a central midfielder."
Bacary Sagna and Carl Jenkinson, Arsenal's two regular right-backs, are also missing through injury.