Two-time Wimbledon champion Andy Murray said 2024 could be his final year before retirement after illness and injury hampered his preparation for the new season.
Murray's year will begin at the Brisbane International as he builds up for the Australian Open later in January.
The 36-year-old is ranked 42nd in the world after a frustrating end to 2023, when he won just one match in his last four tournaments.
Murray has previously battled back from what seemed impending retirement after undergoing hip surgery in 2018.
But he conceded that he will bring down the curtain on his career if the next 12 months follow the same pattern as 2023.
"If I was in a situation like I was at the end of last year, then I probably wouldn't go again," Murray told the BBC.
"But then if physically I'm doing well and my results are good and I'm playing well, then that's enjoyable and I could see myself still playing.
"We'll see how the year goes, see how the body holds up. If things are going well, I'd love to keep going. But if they're not, and I'm not enjoying it, it could be the last year, yes."
Murray, who won Wimbledon in 2013 and 2016 and also took the US Open title in 2012, is part of a golden generation coming towards the end of trophy-laden careers.
Roger Federer retired in 2022 and Rafael Nadal had an injury-blighted 2023, although the Spaniard has suggested he might try to play on beyond 2024.
At 36 Novak Djokovic is still hoping to add to his record 24 Grand Slam titles before hanging up his racket.
Murray revealed the psychological struggle with falling down the rankings after so many years at the top was taking its toll.
"When you have played right at the highest level, it's not that easy when you are going through periods where you are losing in first rounds, and maybe losing matches that you probably should have won," he added.
"At the same time, a couple of years ago if someone had offered me that I'd been playing at top-40 level in the world when I had been struggling with my hip, I would have been happy with that.
"But it is hard, mentally, so I need to do a better job of putting things in perspective this year and be a little bit easier on myself."
Murray faces second seed Grigor Dimitrov in the first round in Brisbane on Monday.
