Diakite, who was an integral part of the Mali squad that finished third at recent the Africa Cup of Nations, has not played for Rangers since the 3-0 reverse to Liverpool in December.
Redknapp signed Jermaine Jenas on loan from Tottenham in January to boost an already congested central midfield which includes Esteban Granero, Stephane Mbia and Ji-Sung Park.
And the Rangers manager expects the Mali international to respond positively to the challenge.
Redknapp said: "His form dipped a little bit before he went away. The Liverpool game was a disappointment.
"And now there's Jermaine Jenas, there's Park, there's Granero and Mbia - we've got a group of them central midfielders.
"But Samba's a good lad, and I like him and he's training well. I guess he could be in the team anytime."