In his column for The Sun, Redknapp wrote: "When it was announced on Tuesday, I - like pretty much the rest of the country - was absolutely gobsmacked that Theo Walcott wasn't in.
"I know it's all about opinions and, let's be honest, there are suddenly millions of football managers out there.
"But, in my view, and I want to stress mine only, if there was one mistake in Fabio Capello's 23, it was not naming Walcott.
"But you only need to look back at that Croatia game in September 2008 when Walcott got his hat-trick to see what a danger he can be.
"Let's face it, if you're going to win the World Cup you need that something special in there and I think he provides it.
"He's a real threat, a match-winner who can turn things your way out of nothing. And, most importantly of all, he genuinely scares people.
"I'd have taken him and all the bookies thought so too as he was 33-1 to miss out."