Defoe, who played under Redknapp at three different clubs, signed an 18-month loan deal at Ibrox in January and the 36-year-old has been backed to hit the goal trail next term.
“Jermain looks after himself so well. He lives right, he’s not a drinker, he’s totally dedicated. Can he get 40 goals? Yes, of course,” Redknapp said, speaking at The John Hartson Foundation Golf Event at Trump Turnberry.
“He will always score goals. He’s an amazing finisher,” he added. “He has such amazing movement and given the chance he will stick them away and I’d expect him to do that next season.
Defoe has scored seven goals for the Light Blues this season, finding the net against Kilmarnock, St Mirren, Aberdeen, Hamilton, Dundee and Hearts on two separate occasions.
And despite his age, Redknapp reckons Defoe isn’t ready to hang his boots up any time soon.
“He will play for another two seasons yet given he is in such good shape,” the former Birmingham boss claimed.
Defoe’s seven goals for the Light Blues means the ex-England striker is just one goal away from reaching 300 in all senior competitions.