And Redknapp has urged Caulker to take his opportunity at Anfield, as he will never get a better one for the rest of his career.
"Steven Caulker has been given the chance of a lifetime at Liverpool and he needs to take this opportunity to get his career back on track," Redknapp said.
"He was a defender full of promise but things stuttered from Cardiff to QPR, where I had him for a while but it didn’t work out, to Southampton, who have hardly used him.
"Steven has only just turned 24 so he has time. Suddenly, almost out of nowhere, he has found himself on loan at one of the greatest clubs in the world and he must seize this chance to get things going again. I really hope he does."
QPR were forced to loan out Caulker as soon as they were relegated from the Premier League, as they could not fund his contract without top level football.
The centre back first moved to Southampton, but he failed to make much of an impression at St. Mary’s.
After an injury crisis, Liverpool have decided to snap the 24-year-old up, to add strength to their defensive options.
Caulker made his debut for Liverpool yesterday against Arsenal, but he actually came on as an emergency striker.
With Liverpool chasing the game, Caulker was utilised up-front, and he has made a good start to life at Anfield, as he helped Jurgen Klopp’s side rescue a point against the Gunners in a 3-3 draw.