Victor Boniface will spend more time on the sidelines after suffering a setback in his recovery from injury.
Boniface has been sidelined since sustaining a thigh injury on international duty last November.
The 25-year-old, however, trained with his teammates before Christmas.
Bayer Leverkusen, however, revealed on Sunday that he has suffered a small setback.
It is now uncertain when he will return to action.
Boniface has registered eight goals and one assist in 15 appearances for Die Werkself this season.
