Spurs' move for the 26-year-old France international was revealed by Sky Sports sources earlier this month, and the Premier League club are trying to strike a deal.
Redknapp worked with Diarra at Portsmouth and he wants to bring him back to England, where he has also featured for Arsenal and Chelsea.
The Spurs boss confirmed that talks are continuing between Real and his own chairman Daniel Levy.
"As for Diarra, I like him," said Redknapp.
"It's a possibility. [The chairman's] been trying for us. He's been trying to do something there."
Source: Team Talk
Source: Team Talk