The Israel international has been without a club since he left Portsmouth in August, but he has been invited to train with the Rs this week.
"I am having a look at him, he's a good defender, he's a good lad and has a great attitude," said Redknapp.
"He looks very fit and I have let him come in and train, we will just see where we go in the next couple of weeks."
Ben Haim has not played any senior football since Israel suffered a 4-0 defeat to Russia in their World Cup qualifier in September.
He is rumoured to be joining Chinese Super League club Guangzhou, who have recently announced the signing of former Everton striker Yakubu.
Guangzhou have claimed Ben Haim has agreed a deal with them, and that he will make his debut in China in January.