Spurs were offered Van Bommel in the January transfer window when Bayern Munich decided to allow the 33-year-old to leave six months before his contract expired. He opted instead to join AC Milan on a five-month deal as Redknapp mulled over whether signing the 33-year-old would be worthwhile.
"I could have took Van Bommel, it was probably a mistake - perhaps I should have taken him," Redknapp said.
"It was a difficult one and I dragged my heels with it. I took my time over it, too long and we didn't do it in the end.
"He would have been a good player for us. Tom (Huddlestone) has had a setback and Van Bommel was on a free, he has signed a five-month contract at AC Milan.
"He gives you experience, he's been there, played Champions League final, World Cup final. He is a proper player for sure but that's how it goes. We could go back for him."
Redknapp was only able to land Steven Pienaar and Bongani Khumalo in what was originally expected to be a busy transfer window for the club.
Chairman Daniel Levy made club record bids for Sergio Aguero and Giuseppe Rossi but neither deal went through and Redknapp watched on as rivals Chelsea spent ?£50million on Fernando Torres and Manchester City splashed ?£27million on Edin Dzeko.
Redknapp admits he was surprised at the fees that changed hands last month, but insists that Tottenham can keep up with their big-spending competitors in the market.
"I had a look at Dzeko last year and they were talking ?£50million and that was too dear, then suddenly he looks cheap at ?£27million," Redknapp said. "I think we can compete though. We have good players here - Gareth Bale is a ?£50million player. If you can find them they are out there."
Source: PA
Source: PA