Spurs have struggled for form in the Premier League this season, taking just five points from a possible 18 over the past few weeks.
Redknapp thinks the problem may lie with Tottenham’s pay structure at the club, with reports suggesting Spurs have a cap of £100,000-a-week.
The former Spurs man questioned whether key members of Spurs’ squad may now be looking enviously at what Walker, who left to join Manchester City in the summer, now earns and that his departure could have set a precedent.
“Letting Kyle Walker go in the summer looks like a huge mistake,” Redknapp said on The Debate.
“I thought it was good business at the time but now what it’s has done is set a precedent in the dressing room. It looks to me that the players know what the going rate is.
“Toby Alderweireld is one of the best centre-backs in the world – why has he not signed? Go and give him whatever he deserves.
“Tottenham have got players anyone in the world would want, but things can quickly slip through your fingers. Once one leaves, then another one. It gives every player an out. They’ve still got a small club mentality there. It’s not changed since I was there.
“These players are well aware of what the going rate is. It’s about going into the England dressing room and seeing a player that plays in your position, knowing he’s getting two or three times what you’re getting a week. It shouldn’t be like that.”