Novak Djokovic will not take part in the augural Laver Cup between Europe and the rest of the world, Roger Federer has confirmed.
The first edition of the new six-man team event is due to take place in Prague in September, when Bjorn Borg of Sweden will captain Europe against a world team led by American John McEnroe.
Djokovic would have qualified automatically courtesy of his status as world number four, but the Serbian, who withdrew from Wimbledon in the quarter-finals due to injury, does not intend to compete.
Addressing the media a day after his triumph over Marin Cilic in the final at the All England Club, Federer, whose management company is jointly staging the Laver Cup, offered an update on the likely participants.
"Novak has already said 'no'. He is expecting another child in that period," the Swiss said.
"I am waiting for an answer from [Andy] Murray. It would be great to have him involved."
World number two Rafael Nadal of Spain is expected to feature alongside long-term rival Federer.