The Scot is currently recuperating after undergoing surgery to fix a hip problem and won’t be able to play for a few months.
Despite the set-back, the 30-year-old is looking to continue his career once he’s fully recovered, and eyes a return to the grand stam stage at this year’s Wimbledon.
Murray already has two Wimbledon titles, along with a US Open crown, but he hasn’t played a competitive match since limping out of last year’s Championships.
Due to the player’s advancing age, the nature of the hip problem, and Murray’s troubled history with injuries, Rusedski feels he may be finished at the very highest level.
He told BBC Radioo Five Live: “If he can get fit, he’s got a shot to get back into the top 100, then top 50 and build his game back.
“But it’s going to take a long while and I wish him all the best because hip surgeries are something that’s difficult to manage.
“I don’t think he will win another Grand Slam, just because of the physical issues he’s had, but I hope he proves me wrong.
“I think he’s done everything he could because usually with a hip problem, you take six months, you hope it comes back good, it didn’t come back the way he’d want so he had no choice but to have the hip surgery and then that’s probably another six months of recuperation.
“If you could look at [Roger] Federer, physically he’s had one surgery in his life, which was a minor meniscus knee surgery and he actually injured his knee in the bathtub of all places when he was bathing his kids, so it wasn’t tennis related.
“If you look at Murray physically, he’s had a lot more difficulties. He’s had back surgery already, his hip surgery, he’s had all sorts of injuries to cope with so for Murray I think it’s going to be a big challenge but he’s one of our greatest sportsmen we’ve ever had in this country and I hope he can come through it, but it’s going to be a big ask.”