The former England international has seen his career take a significant nose dive after once being regarded as one of the best midfielders of his age group.
During his pomp, he was scoring double-digit hauls in the Premier League while providing plenty of assists as he formed a lethal partnership with Harry Kane.
That led him to score 57 goals and rack up 37 assists in the top flight, while also winning 37 caps for England and playing a key role in the Three Lions' journey to the World Cup semi-finals back in 2018.
However since then, the 26-year-old has lost his way.
Alli lost his form and his focus, leading him to drop down the pecking order at Spurs, before landing a fresh start with Everton in January this year, a move that ex-Tottenham boss Redknapp believes was doomed from the start.
Speaking on Kick Off on talkSPORT, Redknapp said: "I called Frank and said, 'take the chance on Dele Alli. He's got fantastic ability and you can get him going'.
"Going to a big club like Everton could give him a big lift and Frank said he was down the road already and I said, 'brilliant, I think he'll be great for you'.
"He was a disaster, a disaster. I watched him play and he loses the ball, he walks and doesn't run, I don't know what's happened to him.
"He's gone to Turkey, where is his career going?
"He turned up to sign for Everton in a Rolls Royce into a working class, council area surrounded by old houses painted blue and white where people live for their football.
"He turned up in a Rolls Royce, who does he think he is?"
Unfortunately, Redknapp believes that Alli is running out of options after once being among the top players in the game.
He said: "I've had more arguments and stuck up for him more than anyone but Frank took a gamble on him and it backfired badly and now he's shipped off to Turkey.
"He was playing for England a few years ago and was one of the best midfield players anywhere.
"He could have gone to Man United, to Liverpool, to Man City or played for anybody during that time at Tottenham, but he's lost it. He's lost that hunger.
"Can he get it back? Why didn't he get it back at Everton? He's running out of options I'm afraid."