The 24-year-old defender is moving to the club from the capital on a two-year deal through to June 30th 2011, with a further one-year appearance-related option.

Looking forward to new challenge

"Christoph Janker is a very versatile player, who can be deployed in a variety of positions at the back", Hertha sporting director Dieter Hoeneß said.

"Moving to Hertha is the next stage in my development as a footballer", Janker commented: "I'm hoping to make as many appearances as possible and am already looking forward to the great atmosphere inside the Olympic Stadium."

No new deal for Chahed

There will be no extension however for right back Sofian Chahed, whose contract is about to run out.

"It wasn't an easy decision for us. Sofian came up through the ranks here and has put in solid performances. But we won't be extending terms with him, because we're well covered on the right with Marc Stein and Lukasz Piszczek. Lukasz played really well over the back end of the season and established himself as another alternative for Chahed's position. Sofian was unlucky with injuries during that period as well", Dieter Hoeneß explained.

Sofian Chahed made 89 Bundesliga appearances for Hertha, scoring four times.