Andy Murray feels he will be “starting from scratch again” when he faces Mackenzie McDonald in the Washington Open first round on Monday.
The tournament will be the 31-year-old’s third since having surgery in January, and his first on a hard court.
Former world number one Murray pulled out of Wimbledon in July as he said it was “too soon” to play five-set matches in his comeback from hip surgery.
“I haven’t been in this position since I was kind of 18,” said Briton Murray.
“It sort of feels like I am starting from scratch again. It’s going to be hard but it should be fun.
“I feel better than I did during the grass [tournaments]. I’ve had another four weeks training and feel pretty good.”
Murray – now ranked 832nd in the world – will face American McDonald after 19:00 local time (00:00 BST). If he wins, will play fellow Briton Kyle Edmund in the second round.
The Scot had hip surgery in January, having been out of action since Wimbledon in 2017, and has only played three ATP Tour matches since his operation.
He made his return in June at Queen’s, where he lost to Nick Kyrgios, and then played at Eastbourne, beating Stan Wawrinka before going out to Edmund.
Murray was last week awarded a wildcard for the Cincinnati Open next month as he tries to build up his match fitness before the US Open, which begins on 27 August.
Also in action in Washington is British number two Katie Boulter, who faces Serbian fifth seed Aleksandra Krunic in the first round of the women’s tournament.
She is joined in the main draw by qualifier and fellow Briton Harriet Dart, who will play sixth seed Belinda Bencic of Switzerland.
In the men’s doubles, Jamie Murray and Brazilian Bruno Soares are seeded fourth and take on Karen Khachanov and Lucas Pouille in the first round.