Redknapp signed defender Samba, 29, in January from Russian outfit Anzhi Makhachkala for £12.5million.
And it was widely thought the R's would offload him after going down.
But Redknapp said: "I'd like to keep him. He'd be the best centre-half in the Championship.
"He's had one bad day since coming here - at Fulham - but he's a good player. We need him back."