Schalke have said plans to extend defender Baba Rahman's loan from Chelsea will depend on his recovery from the knee injury that has kept him out since January.
Ghana international Rahman spent last season on loan at the Bundesliga side, but has been out of action since he was injured at the African Nations Cup.
The left-back made 21 appearances for the Royal Blues before suffering an anterior cruciate ligament tear.
"Our team doctor met Abdul in London. His knee injury is more complex and [his recovery] might be prolonged," Schalke sporting executive Christian Heidel told Bild.
"We will wait another four weeks and then decide with Baba and his agent whether [another loan] makes sense."
Bild said Schalke had reached an agreement with both Chelsea and the player to extend the loan.