IPTL's money worries delay Federer comeback

The 17-time grand slam champion has not played a match since losing to Milos Raonic in the semi-finals of Wimbledon in June.

He subsequently announced he would be taking the rest of the season off in order to recovery fully from the knee surgery he had in February.

The IPTL, an exhibition event that takes place in various Asian cities, was launched in 2014, but financial troubles meant this year's edition was only confirmed eight days prior to the first match on December 2.

The presence of Federer was a major coup, but organisers have now revealed they cannot afford the fees promised to either the 35-year-old Swiss or women's world number two Serena Williams.

Mahesh Bhupathi, founder and managing director of the IPTL, said in a statement: "We have had challenges this year, and we were hoping to get past them.

"With the current economic climate in India and the uncertainty of spending money, I reached out to both Roger and Serena to explain the situation.

"They have been both been very supportive of the IPTL the first two seasons and we look forward to bring them in future years."

Novak Djokovic, Rafael Nadal and Andy Murray have all appeared in previous years, but the highest-profile names to feature this year are Kei Nishikori, Nick Kyrgios and Ana Ivanovic.

Having expanded to six teams in 2015, this year's tournament features only four teams, with matches taking place in Saitama, Singapore and Hyderabad.

Federer will begin his 2017 season at the Hopman Cup in Perth, starting on January 1.