Andy Murray will make a final decision on Tuesday whether he is fit enough to play in the Wimbledon singles later that day.
The 37-year-old Briton, who had a cyst on his back removed nine days ago, is scheduled to play Tomas Machac of the Czech Republic at about 18:30 BST.
Murray is giving himself as long as possible to be ready to play in what will be his Wimbledon farewell.
The two-time champion is planning to retire later this year.
If he is not fit enough for one final appearance in the singles, Murray could still play in the doubles alongside older brother Jamie later this week.
Speaking after practice earlier on Monday, Murray said: “I’ll have a chat with my team, speak to my family this evening and make a decision.
“It’s getting better and the testing I’ve done had been good. I just need to decide whether it’s enough to compete.”
Murray is fighting to be fit because he wants a bit of “closure” at the All England Club before stopping playing professionally.
The former world number one had the cyst close to his spinal cord removed because it was causing nerve pain in his right leg.
On Sunday, Murray said the area where he had the operation was not sore, but added he still did not have 100% feeling in his leg.
He trained with former British number one Kyle Edmund for over an hour on Monday, leading 6-3 2-0 in a practice match before they stopped.
Who else is playing at Wimbledon on Tuesday?
Murray is aiming to be one of 12 Britons playing on day two of this year’s tournament at the All England Club.
British women’s number one Katie Boulter plays German veteran Tatjana Maria about 14:00 BST on Court Three, while Jack Draper – the nation’s leading men’s player – faces Sweden’s Elias Ymer about 16:00 BST on Court Two.
The pair are both seeded at Wimbledon for the first time, having reached career-high rankings following challenging journeys to the top.
Cameron Norrie, who reached the semi-finals in 2022, is also in action, as too are Dan Evans, Harriet Dart, Jacob Fearnley, Paul Jubb, Billy Harris, Henry Searle, Fran Jones and Jan Choinski.
Elsewhere on Tuesday, defending women’s champion Marketa Vondrousova will open play on Centre Court as tradition dictates.
The Czech sixth seed takes on Spain’s Jessica Bouzas Maneiro, before seven-time men’s champion Novak Djokovic faces Czech qualifier Vit Kopriva.
Djokovic, who is looking to match Roger Federer’s record of eight men’s titles, will play for the first time since having knee surgery just 25 days ago.
Over on Court One, 2022 ladies’ champion Elena Rybakina, French Open finalist Alexander Zverev and women’s top seed Iga Swiatek begin their campaigns.
