Former Rangers defender David Bates has begun work with his new side.
Leeds United's on-loan striker has scored 10 goals this season.
The German striker is currently on loan at Elland Road from the Bundesliga side.
Pierre-Michel Lasogga was signed by Leeds United as a replacement for Chris Wood.
The German failed to have the desired impact during his time at White Hart Lane.
Hamburg are reportedly interested in signing Moussa Sissoko from Newcastle United in the summer transfer window.
The Croatian international will be a free agent in the summer.
The Hungarian international is surplus to requirements at the Bundesliga club.
The Hamburg man is not wanted at the Bundesliga club.
The Magpies are said to be keen on the player as doubts emerge over Papiss Cisse's future.
The German international has had a tough season with injury and form.
Muhamed Besic seems a good signing but he does have a chequered past in the game.
A transfer pursuit in Germany involving a star Liverpool and Arsenal were reported to want, has turned sour.