A player with huge amounts of Premier League experience had been recruited to provide competition to Alfredo Morelos.
It was a significant upgrade on those who have been competing with the Colombian for the place in the Rangers team.
In turn Defoe has hit 23 goals in 47 appearances.
The 37-year-old's 18-month loan deal from Bournemouth comes to an end in May whereby he will be a free agent.
Rangers boss Steven Gerrard has been open about extending the striker's deal.
In December he said: "I’m hoping it’s a formality but until it is done and signed, it’s not. Are others maybe looking at him, though?
“If you can name me a team who can offer him what we are offering him in terms of size of club, in terms of opportunity at his age, in terms of the dressing room, the respect he has from the staff and the players, then I’ll have a debate with you.
“He has everything here that he needs. It is a fantastic club and he is going to get more opportunities."
However, experienced striker Kevin Phillips reckons it is not a formality.
“Possibly, I think it just depends on what Jermain wants to do," he told Football Insider. "He strikes me as he just wants to play football for as long as he can.
“I can see it still looks like he’s got that enthusiasm for the game, that love of the game and you know what?
“It wouldn’t surprise me if Rangers didn’t take it up, there would be teams in the Championship or lower end of the Premier League queuing up to take him because they know he’s guaranteed to get you goals, important goals when you need it.
“So it will be interesting to see what they do the end of the season.”