Lin Dan of China reacts during his men's singles first round match against compatriot Chen Long at the Fuzhou China Open badminton tournament in Fuzhou in China's eastern Fujian province on Nov 6, 2019. (STR / OSPORTS / AFP)

BEIJING - With one month to go before the Tokyo Olympic Games open, athletes across the globe are sweating on their preparations for the rescheduled sporting extravaganza.

But some prominent names will not be seen in Tokyo for various reasons. Some have called an end to their careers, some were forced to withdraw through injuries or illness, while others are serving suspensions.

Retirement

Chinese badminton legend Lin Dan, who had attempted to make his fifth Olympic appearance in Tokyo, ended his illustrious 20-year career on July 4, 2020, saying it would be too much to ask of his 37-year-old body

The COVID-19 pandemic has wreaked havoc on the world, and sports is no exception. Postponing the Tokyo Olympic Games by one year has impacted athletes' preparations, especially for veterans who were planning to retire after Tokyo 2020 last year.

Chinese badminton legend Lin Dan, who had attempted to make his fifth Olympic appearance in Tokyo, ended his illustrious 20-year career on July 4, 2020, saying it would be too much to ask of his 37-year-old body.

Belgian swimmer Pieter Timmers, who won the men's 100m freestyle silver medal in Rio, had to retire last November after the year-long postponement thwarted his watertight plan, which had been designed years ago to "give everything once more at the Games, and then start a new chapter."

Japanese Olympic badminton champion Ayaka Takahashi was also forced to bid farewell to her career.

"After the announcement of the postponement of Tokyo 2020, I thought I could not keep my motivation high enough to go through another tough year," she said.

ALSO READ: Badminton: World No 1 Tai plans to play on until at least 2021

It's quite natural that veterans have to weigh the pros and cons of the postponement of their careers before making decisions.

Spain's Rafael Nadal celebrates after defeating Britain's Cameron Norrie during their third round match on day 7, of the French Open tennis tournament at Roland Garros in Paris, France on June 5, 2021. (MICHEL EULER / AP)

Injuries

For me, like all athletes, taking part in the Olympics and representing my country is a huge honor and that makes this decision even tougher. However, 2021 did not start as expected and I don't feel ready to play my best in Tokyo.

Rafael Nadal, Spanish tennis star

A batch of athletes decided to skip the Tokyo 2020 Games, either through injuries or fitness issues.

On June 1, Olympic badminton gold medalist Carolina Marin said that she would not be able to defend her title in Tokyo after having torn the meniscus and anterior cruciate ligaments in her left knee.

Two-time Olympic triple-jump champion Christian Taylor cannot strive for a three-peat after rupturing an Achilles tendon in a match in May. The four-time world champion later underwent surgery to repair his torn Achilles and will miss the Tokyo Games.

After failing to extend his winning record in the French Open, Spanish tennis star Rafael Nadal confirmed that he has withdrawn from the upcoming Wimbledon tournament and the Tokyo Olympics.

"The goal is to prolong my career and continue to do what makes me happy, that is to compete at the highest level and keep fighting for those professional and personal goals at the maximum level of competition," explained the 35-year-old Nadal.

ALSO READ: Nadal pulls out of Wimbledon and Olympics to prolong career

He was later joined in the Olympic absentees by Dominic Thiem, who had suffered a first-round exit at Roland Garros.

"For me, like all athletes, taking part in the Olympics and representing my country is a huge honor and that makes this decision even tougher. However, 2021 did not start as expected and I don't feel ready to play my best in Tokyo," said Thiem.

The Austrian, however, didn't rule out his Olympic hope for the future.

"I am young and I hope to be able to play for Austria at the Olympics in Paris 2024," he added.

In this file photo dated Aug 14, 2016, South Africa's Luvo Manyonga poses with his silver medal during the long jump medals at the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil. (KRISTY WIGGLESWORTH / AP, FILE)

Penalty

Due to three violations of whereabouts rules in a one-year period, Olympic long jump silver medalist Luvo Manyonga from South Africa was banned for four years in June

Also worth a moment of lamenting are those who have to serve out suspensions over doping offenses.

Men's 100m world champion Christian Coleman was banned for two years last October, as Athletics Integrity Unit found him three violations of doping control rules.

The American sprinter had his ban reduced to 18 months after appealing to the Court of Arbitration for Sport (CAS). But the suspension won't expire until November, meaning he still could not compete in Tokyo this summer.

World and Olympic champion Sun Yang's hopes of competing at the Tokyo Games have been ended after the CAS reduced the Chinese swimmer's ban for doping violations to four years and three months from eight years.

Sun was banned after he and members of his entourage were found to have smashed vials containing blood samples taken at an out-of-competition test in September 2018.

Due to three violations of whereabouts rules in a one-year period, Olympic long jump silver medalist Luvo Manyonga from South Africa was banned for four years in June.

It was the 30-year-old Manyonga's second doping case, thus leading to doubling the usual two-year ban for whereabouts violations.

Starting from December 23, 2020, Manyonga's ban runs into the end of 2024, meaning he will miss the next two Summer Games in Tokyo and Paris.

Another track and field star unable to feature in Tokyo is Elijah Manangoi from Kenya. The 2017 men's 1,500m world champion missed three tests within less than half a year and has been banned through December 2021.

READ MORE: Sun Yang says will appeal CAS ruling to uphold ban

While some stars will be missing from Tokyo, but when the cauldron is ignited at the opening ceremony on July 23, there will be a new generation of athletes eyeing to take over the mantle