Three-time grand slam winner Andy Murray said his singles return may be closer than he originally thought.
The 32-year-old has so far been restricted to doubles action since returning to the game following his hip resurfacing operation in January, winning his first tournament back at Queen's in June before suffering early exits at Eastbourne and Wimbledon.
He will link up with brother Jamie at next week's Citi Open in Washington.
Speaking ahead of the tournament of his return to singles action, he told reporters: "I'm closer than maybe what I thought I was."
Murray added that a return to the hard courts in August was in his sights, and if not, then he would wait until after the US Open.
He said: "Best-case scenario probably would be Cincinnati. And then if I wasn't able to play in Cincinnati, there's a good chance I would probably wait until after New York, because I wouldn't want my first tournament, either, to be playing best-of-five."
Murray's last grand slam appearance was on the hard courts of Melbourne, where he was dispatched in the first round by quarter-finalist Roberto Bautista Agut in four sets.
The Murray brothers last played together at the Rio Olympics, but were a prolific partnership during Great Britain's 2015 Davis Cup victory, while they have won two ATP Tour titles together, in Tokyo in 2011 and Valencia the year before.
Former world number one Novak Djokovic has suffered another early defeat as Slovakia's Martin Klizan won their second round match at the Barcelona Open.
Djokovic has now won just two of five matches since the Australian Open, where he was beaten by Chung Hyeon, after a 6-2 1-6 6-3 loss at Sabadell on Wednesday. Klizan converted all three of his break-point opportunities to prevail.
After losing to Dominic Thiem of Austria at the Monte Carlo Masters last week, the 30-year-old Serb experienced another defeat ahead of the French Open at Roland Garros, which begins on May 22.
Djokovic suffered early exits at the Miami Open, losing to Frenchman Benoit Paire earlier this month, and last month at Indian Wells, where Japan's Daniel Taro was the victor. He has not reached the last eight of a tournament since Wimbledon 2017 and has struggled with a long-term elbow injury.
Klizan, a qualifier and world number 140, will meet Feliciano Lopez in the quarter-finals after the Spaniard's win over Serbia's Dusan Lajovic on Tuesday.
Top seed Rafael Nadal and second seed Grigor Dimitrov of Bulgaria experienced no such problems, but Japan's Kei Nishikori retired after losing the first set to Guillermo Garcia-Lopez. Nishikori had an issue with his right wrist.
Nadal beat fellow Spaniard Roberto Carballes Baena 6-4 6-4 to win his 37th and 38th consecutive sets on clay, breaking a record he had jointly held with Ilie Nastase of Romania.
Nadal has now won 15 successive matches on the surface and next plays Garcia-Lopez.