article_snippet.sent: The 19-year-old has not featured for the first team since March last year after suffering serious knee injury .
article_snippet.sent: The Germany Under-21 international played for Arsenal's development squad as they lost 1-0 to Reading on Monday and is now over a serious knee injury worries. '
highlights_snippet.sent: Midfielder has been out for more than a year after with serious knee injury .
  
highlights_snippet.sent: Arsenal have doubts over signing Liverpool star Raheem Sterling .