The Greek stopper has been out of action since undergoing surgery on his knee last November, reducing him to only ten Bundesliga appearances last season.
Road to recovery
His club announced on Tuesday that he was to start following an individual training regime in a bid to have him fit and ready for the start of the 2013/14 campaign. Schalke open their season at home to Hamburger SV on Sunday, 11 August.
The 21-year-old joined the Royal Blues from Olympiacos FC in 2010 and has made a total of 57 appearances in the German top flight, scoring three goals.