Arsène Wenger believes Thomas Vermaelen will prove his quality in Arsenal's upcoming games.
But with Koscielny sidelined through injury, Vermaelen has stepped in at the heart of the Gunners' defence and is likely to continue there for Saturday's Premier League clash with Manchester City.
He has an opportunity to show how good he is and I'm sure he will take itArsène Wenger
"We know Thomas has paid a heavy price for having Laurent and Per who worked well together," Wenger told Arsenal Player. "But he has an opportunity to show how good he is and I'm sure he will take it."
Loan signing Kim Kallstrom made his debut for the club in Tuesday's 2-2 draw at home to Swansea City and the Arsenal manager praised the Swede's professionalism since he arrived in north London.
"He has an absolutely fantastic attitude," Wenger said. "He's a credit to the job because of his attitude, his focus and his determination. He works hard, he's helpful and he's marvellous.
"I'm convinced that he can be important for starting or coming on in the games because he has the experience, he has quality and his attitude is fantastic."