Schalke's Kirchhoff to undergo ankle surgery
Kirchhoff, who can also feature in midfield, joined Schalke on loan from Bayern Munich in December in an attempt to secure more first-team football.
But the 23-year-old is now set for a lengthy spell on the sidelines after Schalke announced that the former Mainz player had torn ligaments in his ankle in an injury sustained at the club's mid-season training camp in Qatar.
A statement on Schalke's official website read: "Jan Kirchhoff underwent a further examination on Tuesday after his premature departure from the club's mid-season training camp.
"An MRI scan conducted by Dr Hans-Wilhelm Muller-Wohlfahrt in Munich revealed that the new signing, who injured his right ankle in a challenge on the second day of training in Qatar, has torn the anterior syndesmotic ligament.
"As a result of the diagnosis Kirchhoff will undergo surgery in Tubingen on Wednesday. The 23-year-old defensive player will be out of action for several weeks."