The 29-year-old midfielder reportedly fell out with Lokomotiv manager Leonid Kuchuk and then refused to train with the squad, and as a result Diarra is said to be heading to London for talks with Queens Park Rangers.
Diarra left Portsmouth to join Real Madrid, where he made 87 appearances before moving to Russia in 2012 where he played for Anzhi Makhachkala and most recently Lokomotiv Moscow.
The former Chelsea and Arsenal man was linked with a move to Loftus Road earlier this month but his high wage demands made any move unlikely.
Although following his exit from Lokomotiv, Diarra is believed to be willing to take a pay-cut in order to seal a move to QPR.
Redknapp has already added two midfielders this summer in Jordon Mutch and Leroy Fer, though Diarra will offer valuable experience in the centre of midfield to partner the likes of Fer and Barton.
His defensive qualities will serve the R's well as he can offer protection to the back four and is certainly someone who will add quality to the squad.