Who's missing from Rio?

The 2016 Rio Games will lose some of its sheen after some of the sporting world's biggest stars have pulled out from the event due to various reasons.

Seventeen-time Grand Slam champion Roger Federer opted out of the Rio Games as he's rehabilitating from an injury.   -  Getty Images

When Swiss great Roger Federer announced that injury concerns had forced him out of Rio 2016, it dawned on tennis fans that he may have lost his final chance to add an Olympic singles gold medal to an impressive list of triumphs.

At 34, time is running out for the 17-time Grand Slam champion. It appears that Federer will have to be content with the doubles title won in Beijing 2008, and the singles silver medal gained at London 2012.

While Federer had little choice but to skip Olympic duty, USA’s basketball superstar Lebron James simply opted out. James, the finals MVP in Cleveland Cavaliers’ march to the NBA title recently, stated that he could use the rest. His chief rival in that final, Golden State’s shooting machine Stephen Curry, also made himself unavailable for selection, citing “several factors – including recent ankle and knee injuries”.

Argentina’s football magician, Lionel Messi, walked a similar path. A packed season - for both club and country - would leave him exhausted, and his intentions to withdraw were first revealed six months ago.

This intent gained credence when the playmaker retired from international football, after failing to guide Argentina past Chile in the Copa America final in June.

Meanwhile, Yelena Isinbayeva, the two-time Olympic pole vault champion fought the International Association of Athletic Federations' (IAAF) decision to enforce a blanket ban on Russian track and field athletes, following claims that the country ran a state-sponsored doping programme.

Yelena’s appeal for exemption, however, was rejected by the IAAF on Friday. At a ceremony held at Moscow for Russia’s Rio-bound athletes, an emotional Yelena called on her peers to “show them what you're able to do - for yourself and for us (banned athletes) too."

Closer home, Manipuri boxing sensation Mary Kom battled the odds and came up short as well. Mary, a five-time world amateur champion and 2012 London Games bronze medalist, failed to make the cut after a poor show in the qualification events. A last-ditch attempt to obtain a tripartite commission place fell flat too.

The 33-year-old later apologised to the nation, saying, ”To the people of India, I am so sorry.”

Other notable absentees:

Basketball: Anthony Davis (USA), Marc Gasol (Spain), Blake Griffin (USA), James Harden (USA), Russell Westbrook (USA) and Kristaps Porzingis (Latvia).

Golf: Jason Day (Australia), Dustin Johnson (USA), Jordan Spieth (USA), Tiger Woods (USA), Rory McIlroy (Ireland) and Vijay Singh (Fiji).

Tennis: Tomas Berdych (Czech Republic), Milos Raonic (Canada), Simona Halep (Romania) and Maria Sharapova (Russia).

Cycling: Alberto Contador (Spain).