Baba Rahman
Rahman's serious knee injury could still scupper a proposed return to Schalke Reuters

Abdul "Baba" Rahman's proposed switch from Chelsea to Schalke hangs in the balance, with the full-back's "complex" knee injury throwing the move into jeopardy.

Rahman, 22, was given permission to leave Stamford Bridge on loan last summer after Blues boss Antonio Conte judged the full-back to be "too attacking", according to the player himself.

The Ghana international suffered a serious knee injury during January's Africa Cup of Nations which ruled him out for the remainder of the 2016-17 season.

Despite that, Schalke had seemingly seen enough from the defender, and suggested in May they would bring him back for another spell at the club. Rival left-back Sead Kolasinac recently left the Bundesliga side to join Arsenal.

But Bild suggest Schalke are now having second thoughts having discovered the injury is more complicated than first feared and could keep him out until October.

The club's sporting director, Christian Heidel, told the publication: "Our team doctor met Abdul in London. His knee injury is more and complex and potentially lengthy. We will wait for another four weeks and then decide with Baba and his advisor whether [another loan] makes sense."

Rahman signed for Chelsea during the summer of 2015 for £21m ($27.1m), but made just 11 appearances for the club during his debut season. According to the Daily Mail, Everton have also made their interest in the player known, with Ronald Koeman keen to shore up the left-hand side of his defence.

Chelsea are expected to sanction a number of loan exits this summer with 37 of their players shipping out across the UK and Europe last season. Some of those deals have already been made permanent, with Juan Cuadrado and Christian Atsu extending their stays at Juventus and Newcastle United respectively.