Roger Federer of Switzerland lost 6-3, 6-4 to Alexander Zverev of Germany during Rogers Cup final at Uniprix Stadium in Montreal, Quebec, Canada. Image Credit: AFP

Cincinnati: There is another addition to the injury epidemic that has blown up in tennis over the past couple of months, and this time it affects the man of the moment: Wimbledon and Australian Open champion Roger Federer, who has withdrawn from this week’s Cincinnati Masters because of back trouble.

Many observers suspected that Federer was struggling when he lost to Alexander Zverev in the Rogers Cup final on Sunday. One of his many remarkable achievements is that he has never retired during any of his 1,363 matches on the ATP Tour, but a less defiant character might have walked off the court rather than fight through — as Federer did — to the end of a 6-3, 6-4 defeat.

The problem was one of mobility and flexibility. As the match moved into the second set, Federer lacked his usual snap, particularly on his serve, which became so static that he was only able to roll the ball in at a gentle pace.

“I tweaked my back in Montreal,” he confirmed on Monday as he withdrew from the ATP Masters 1000 event in Cincinnati. The high attrition rate on the men’s tour at the moment means that only one of the world’s top six will be competing this week. That man is Rafael Nadal, who has proved surprisingly robust this year after the wrist-tendon tear that spoiled his 2016 season.

Nadal’s reward for maintaining his structural integrity — as well as for utterly dominating the European clay-court swing — is that he will succeed Andy Murray as world No 1 on Monday, even if he should lose his opening match against either Richard Gasquet or John-Patrick Smith.

It is the fourth time Nadal has been on top of the rankings, having already spent 141 weeks there. This will be the 11th time that the No 1 spot has changed hands between the members of the “Big Four” since Federer first occupied it on February 2, 2004.

Murray is among the big names sidelined by injury, although it is expected that he will try to play the US Open — which starts on August 28 — despite the chronic hip trouble he has been dealing with since the French Open. Both Novak Djokovic and Stan Wawrinka have already announced that they will not be appearing again in 2017, while the 2014 US Open champion Marin Cilic is nursing a groin issue.

As for Federer, he now has a fortnight to recover from whatever the problem is with his back. Even the man himself may not yet know how serious the injury is. But he will remember that back trouble ruined the majority of his 2013 season — a year in which his winning percentage dropped from its usual level in the low 80s to a moderate 73.

Speaking to The Daily Telegraph in April, Federer recalled that “the back struck in 2013, in Indian Wells. I had three weeks of pain and I was just not well at all there. Back pain isn’t something that goes away very quickly. It’s like a cloud in your head, it makes you unhappy and you are disappointed that your connection [with the ball] doesn’t come back”.

Cincinnati — a mixed-gender tournament which many players use as their final build-up event before the US Open — is also missing some of the leading women. Maria Sharapova has pulled out with a forearm issue and Victoria Azarenka is absent because of personal problems.

Meanwhile, Timea Bacsinszky, the ex-French Open semi-finalist, has announced that she will not play the US Open because of a thigh injury. And Bernard Tomic and Gael Monfils came up with last-minute excuses on Monday for not playing in Cincinnati, both citing illness.