Andy Murray was forced to withdraw from the Canadian Open before his third-round showdown with Italy's Jannik Sinner due to an abdominal problem.

The three-time major winner had defeated Lorenzo Sonego and Max Purcell en route to the last eight and was due to face the former's compatriot for a place in the quarter-finals.

Murray came out onto the court on Thursday in anticipation of his meeting with Sonego, which would have been his first last-16 appearance since going all the way in the 2015 Canadian Open.

However, the 36-year-old instead informed the crowd that he would be forced to pull out of the contest due to an abdominal strain, which was just the seventh walkover that he has conceded during his career.

Addressing the fans in the arena, Murray admitted that he felt "terrible" to be departing in such a manner, as he is unsure if he will compete at the Canadian Open again.

"I have an issue with my abdominal so unfortunately I'm not going to be able to play this evening. I'm really sorry," the three-time Canada Masters champion said on the court.

"I feel like I've let you down. I've rarely been in this situation in my career and I feel terrible. I don't know, this might be my last time playing here as well. So to finish like this feels rubbish."

Later, Murray revealed that he had been suffering from a similar problem in the build-up to last year's Queen's Club Championships, which he was forced to miss before being given the green light to compete at Wimbledon.

"I had a very similar issue last year in the tournament in Stuttgart before Wimbledon which forced me to miss the Queen's Club tournament and I was able to play Wimbledon," Murray added.

"It took me about 10 to 12 days before I was feeling good again. This is not as bad as that but obviously the danger if you compete and play on it is you make it worse.

"So, I'll need to see how it develops over the coming days and hopefully feel better in a few days. I'm really sorry. Thank you."

Sinner's walkover win means that the 21-year-old will face France's Gael Monfils in the quarter-finals, while Murray will bid to recover in time for the upcoming US Open, which begins on August 28.

The Briton's injury concern comes after 2022 Wimbledon finalist Nick Kyrgios withdrew from this year's US Open citing his wrist injury, meaning that the Australian will have missed all four Grand Slams in 2023.