The striker has started just four games in The Premier League, since his £6 million move from Preston in the summer.
But the 22-year-old will now look to relaunch his career at Portman Road after the two clubs agreed on a loan fee.
"It should be tied up in the next few days. It's a good deal for us financially too which is important," Redknapp told BBC Radio Solent.
Peter Storrie has been dealing with their chairman, and they've made a good offer. Lots of club have asked about taking David, but Ipswich are the only ones to come forward with a decent offer.
"David is interested in going, so we're just waiting for his injury to clear up, which should be in the next few days."