The 6ft 6ins centre-back is set for a swift return to Germany at the Signal Iduna Park next week.
Wenger is confident the German international will prove a sound investment, at a reported £8million certainly cheaper than what Arsenal would have been forced to pay out to close a deal for England defender Gary Cahill at Bolton.
"For us it was interesting - he is more a reader of the game, rather than a physical player," Wenger told a news conference.
"He's tall, is only 26 and he was affordable for us."
Wenger insists he never looks at passports, just what the player can add to the group.
"You just want to play with a good mentality," the Arsenal manager said.
"Usually the English players, defenders, they have a good mentality. You cannot fault them for that, and for me the Germans are similar."