0847 GMT October 14, 2019
The Swiss icon was eliminated at the quarterfinal stage of the US Open by Grigor Dimitrov, going down 3-6, 6-4, 3-6, 6-4, 6-2 to the Bulgarian, express.co.uk reported.
Federer was hoping to reach a first US Open final since 2008, where it was thought he might meet Rafael Nadal.
But the 38-year-old's second week at Flushing Meadows was cut short earlier than he will have hoped.
And Federer appeared to be affected by his back injury, which required a medical timeout in the fifth set, despite protesting afterwards that he could play through the pain after completing the match.
The 20-time Grand Slam champion will now end the 2019 season without a Major victory this year despite competing in all four events – the Australian Open, the French Open, Wimbledon and the US Open – for the first time since 2015.
But he will hope to add to his tally of 101 ATP Tour titles, with Federer expected back for the Shanghai Masters in early October.
Asked what tournaments he plans to play in for the rest of the year, Federer replied: "I mean, the whole thing? I don't know.
"I guess Laver Cup, Shanghai, Basel, maybe Paris, London. That's the schedule for now.
"I don't know if the team have other ideas or not.
"I'm happy to get a bit of a break now, go back to practice, reassess and attack from there."
Before Shanghai, Federer will play for Team Europe in the Laver Cup in Geneva, Switzerland on September 20.
The veteran will join forces with Nadal, Dominic Thiem, Alexander Zverev, Stefanos Tsitsipas and Fabio Fognini for the Bjorn Borg-captained team.
Team World - captained by John McEnroe – consists of John Isner, Kevin Anderson, Milos Raonic, Nick Kyrgios, Denis Shapovalov and one other player still to be determined.
Team Europe has won the tournament in both of the two years since it began, Federer beating both Kyrgios and Isner in the singles in 2018.
Explaining how the Laver Cup came to be, CEO Steve Zacks told CNN Money earlier this year: "The idea came when Roger Federer wanted to do something to recognize Rod Laver.
"He was doing an event with Rod and he thought that he could make more money in a day than Laver in his whole career.
"He wanted to do something to give back and the Laver Cup was born from that."