The club captain has been stuck on the bench in recent weeks.
"He took it in a remarkable way [when he lost his place]," the Arsenal manager said.
"He is a great man and I didn't make him captain by coincidence. I knew there is something mentally special there.
"Vermaelen responds in positive situations and in less positive situations like when you don't play
."They know there could be rotation with the three centre backs from the start of the season, depending on good and less good periods of any individual player. He [Vermaelen] took that remarkably well."