Fifth-placed Spurs are currently four points off the Champions League places after winning just three of their last 14 Premier League games.
Corluka, who is on loan at Bayer Levekusen, believes that Redknapp's failure to rotate his squad has cost them.
"I wouldn't be surprised if they finished sixth," said the Croatian. "[Redknapp] didn't rotate enough. That's the main problem.
"I watched almost every Spurs game and they played them all with the same 11, 12, 13 players, and that's why the players now are really tired."
Redknapp's side continue their quest for European football this weekend when they host struggling Blackburn Rovers.