Former world number four Greg Rusedski doubts whether Andy Murray can win another Grand Slam title.
Murray, 30, is recovering from hip surgery and could miss up to a year of action before he is fully fit.
The Scot has won Wimbledon twice and the US Open.
“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,” said Rusedski, who reached the US Open final in 1997, on BBC Radio 5 live.
“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.”
Rusedski was asked how Murray’s situation compares to Roger Federer’s absence in 2016, after which he won the Australian Open and Wimbledon.
“I think Andy’s got a lot more to overcome to be frank,” Rusedski said. “If you could look at 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.”