29-year-old Diarra was last playing with Lokomotiv Moscow in Russia, but following his departure from the club in the summer of 2014, he was linked with moves to QPR - as per the Daily Mail - as well as Celtic - as per the Herald.
Neither move came to fruition at the start of the season, and the former Chelsea and Arsenal star has since been training with West Ham’s head of medicine to keep up his fitness levels - as reported by the previously linked Mail story - and potentially entice any future employers.
Whilst his talents are best on display in England for any clubs that would be looking to sign him, the French international looks as if he could be heading to a country he has yet to play in during his career, with German side Borussia Dortmund reportedly keen on signing him to overcome their injury woes.
As outlined by L’Equipe, Jurgen Klopp is keen on the midfielder to add experience to his side, and is preparing to approach Diarra over a move - with him available for free.
Sebastian Kehl sustained an injury in Dortmund’s recent friendly against Steaua Bucharest, meaning Diarra would be able to fill in his defensive midfield position whilst he recovers. Right-back Kevin Grosskreutz allso picked up an ankle injury in that game, and Diarra used to perform in the full-back position when breaking through at Stamford Bridge.