Arsenal must keep a close eye on Norwich striker Ricky van Wolfswinkel, says Thomas Vermaelen.
The Arsenal captain, speaking to the club's official site, pinpointed the Dutch forward as one of the main threats to the Gunners this weekend.
Vermaelen - who has struggled to win a starting spot this season - played against the striker when the pair were plying their trade in the Eredevisie.
Whilst the Belgium defender was turning out for Ajax, van Wolfswinkel was a youngster coming through at Vitesse.
The Dutchman went to Sporting Lisbon and has continued to impress with his goals.
Van Wolfswinkel is expected to lead the line for the Canaries at the Emirates on Saturday, and Vermaelen is aware of the threat he poses:
"Norwich have some good players, including Ricky van Wolfswinkel, who I know very well from my time in Holland," said Vermaelen.
"I played against him when he first came through into the first team at Vitesse and he then went to Utrecht and abroad to Portugal and [always] scored a lot of goals.
"He is a clinical goalscorer, he makes good runs and is someone that we will definitely need to watch closely."
Arsenal will be looking to maintain their status as league-leaders, and have been boosted by news that Mesut Ozil is fit for the tie.
Vermaelen will likely watch from the sides as the Gunners look to record another win.