The Germans are currently at the top of Group E with six points from their opening two fixtures, while Chelsea sit in third place following one win and one defeat.
Terry, who will start the match at the Veltins-Arena, understands that the Blues are by no means guaranteed an easy victory.
"They're a real threat going forward and defensively they've looked solid in the games I've seen," he told reporters. "We understand it's going to be a tough game.
"I've seen highlights of their previous Champions League games, we're not coming here under false pretences thinking we're going to pick up three points easily, we understand it's going to be a tough night."