Is this the end of the road for Roger Federer?

FILE - In this Jan. 30, 2020, file photo, Switzerland's Roger Federer speaks during a press conference following his semifinal loss to Serbia's Novak Djokovic at the Australian Open tennis championship in Melbourne, Australia. Federer leads the annual Forbes ranking of highest-paid athletes with what the magazine says is $106.3 million in total earnings. He is the first tennis player top the list since it was first compiled in 1990. [AP Photo/Dita Alangkara, File]

Roger Federer is talking optimistically about returning to his “highest level” after knee surgery, but does tennis have to start adjusting to a future without the Swiss star?

The 20-time Grand Slam winner announced on Wednesday that he would be sidelined until 2021 after his second operation in a matter of months.

In some ways 2020 is a good season to miss after the coronavirus ravaged the tennis schedule.

Writing Federer off in the past has proved dangerous.

He returned from a six-month injury lay-off to claim the Australian Open in 2017, winning his eighth Wimbledon crown later that year.

But he will be 40 in 2021 and is now heading into uncharted territory.

Despite his groaning trophy cabinet, there are two factors that will motivate Federer to keep going - the risk of losing his grip on the men’s Grand Slam title record and a missing Olympics singles gold medal.

Rafael Nadal has 19 majors, just one shy of Federer’s mark and Djokovic has 17.

Spain’s Nadal will be fancied to draw level with Federer at the French Open, rescheduled for September, while few would bet against Djokovic winning in New York weeks earlier.

In April, Federer said he was “devastated” when Wimbledon was cancelled for the first time since World War II.

Last year he fell agonisingly short at the All England Club, failing to convert two championship points on his own serve against Djokovic.

The Wimbledon grass probably remains his best chance of adding to his Grand Slam collection -- he has not won the US Open since 2008 and his only title at Roland Garros came in 2009.

Even though Federer has slipped from the very pinnacle of the game, he is still a major threat to Nadal and Djokovic.

 Last year, the world number four had a 53-10 win-loss record and he reached the semi-finals at the Australian Open in January in his only tournament this year.

Federer, who is still six ATP titles short of Jimmy Connors’ all-time record of 109, has one glaring omission from his CV - the Olympic title.

The Swiss won doubles gold in Beijing in 2008 with compatriot Stan Wawrinka but lost in the singles final to Andy Murray in London four years later.

The postponed Tokyo Games will almost certainly be Federer’s last opportunity to complete a career “golden” Grand Slam - he will turn 40 on the day of the closing ceremony next year.

Tennis will feel the loss of the elegant Federer keenly when he walks off the court for the last time.

Djokovic and Nadal have been the dominant forces in recent years.