Redknapp only has Wilson Palacios, Tom Huddlestone and Jermaine Jenas as central midfielders and views the 20-year-old, who made his Brazil debut earlier in the season, as a possibility to provide competition.
"We've only got three central midfield players," Redknapp said.
"Jamie O'Hara went, Kevin-Prince Boateng went, Didier Zokora went. Suddenly we're very, very short in there. Jermaine Jenas is on four bookings, Palacios on three.
"So I'm looking for someone else who can play in midfield here. We've been looking at Sandro. He's just breaking into the Brazilian team from the Under-21s. He can play - he's a modern day midfield player.
"I'd like to go and have a look myself as well and, if we do decide to do anything, it'll be up to the chairman to push it on from there."