Barton was loaned to the French club after being ruled out of the opening 12 matches of the season through suspension, and Redknapp has admitted that he would not be surprised if the 30-year-old remained at the Ligue 1 side.
The former Spurs boss told reporters: "Joey has done well, he's been excellent at Marseille. He's had a great season for them.
"He's been good. I've seen Marseille play this year and he's done ever so well for them. If you saw where Joey lived in Marseille, I think it would be very difficult to get him back.
"Joey has a nice lifestyle there. I'd be surprised really if he wanted to come back."
The former Newcastle United and Manchester City midfielder has scored once in 25 games in France.