2020 Tokyo Games for Roger Federer? Why not?

It turns out Rio de Janeiro won't be a terminal destination for Roger Federer. The upcoming Olympics were where the 34-year-old all-time men's Grand Slam singles champ was destined to go out in a blaze of glory -- or a tailspin.

But Rio has become just another station that Federer bypasses without pause as he continues his unique journey in tennis, the terminus still unknown. That much was clear in the undertone of the announcement Federer posted the other day, declaring that he was skipping the Olympic Games and pulling the plug on the rest of the 2016 year.

Instead, he will focus on "extensive rehabilitation" of his surgically repaired left knee.

"The doctors advised that if I want to play on the ATP World Tour injury-free for another few years, as I intend to do, I must give both my knee and body the proper time to fully recover," Federer wrote on his Facebook page.

Note his reference to "another few years," and the added emphasis immediately thereafter.

Federer may not be ready to revise his timeline and declare that he wants to play through until the Tokyo Olympic Games of 2020. But who's to say he couldn't do it?

His decision to take the rest of the year off instead of mounting a retirement tour speaks volumes. It implies a long-term commitment. He wants to strengthen that left knee over a long, five-month period, presumably because he feels it still has a lot more work to do.

Back in 2012, when Federer first declared that he intended to play on the ATP Tour at least until the Rio Games, some scoffed at his plans. Sure, he was a 17-time Grand Slam singles champion -- the most prolific in the game's history. But he was 30 years old, pressed on all sides by younger men, including Novak Djokovic and Andy Murray.

But Federer held his own, and then some. True, Federer hasn't won a Grand Slam tournament since his triumph at Wimbledon four years ago. That conquest was followed on the same Centre Court a few weeks later by a painful loss in the gold medal Olympic Games match to Murray. The failure helped crystallize Federer's determination to play on, hoping for another crack at the golden prize in Rio.

If the singles gold medal remains the only hole in Federer's résumé, it has also been a source of motivational fuel. After their Olympic gold medal clash, Federer won six of eight from Murray. In 2015, a healthy Federer was a respectable 3-5 against the rampaging Djokovic. Federer was building steam toward that date in Rio.

Then in late January of this year, Federer heard a "click" and felt a stab of pain in his left knee while drawing a bath for his children. It led to surgery, a hurried rehabilitation, missed time. If only he had taught his twins to shower, Federer might have gone into Rio seeded even higher than his current No. 3 ranking would mandate.

Now, the fruit of his sustained excellence over four years is sharp disappointment. But it's far from the end of anything.

Federer took a spill at this year's Wimbledon late in a semifinal loss to Milos Raonic. It was an uncharacteristically ungainly fall. To some, it appeared symbolic. But perhaps it wasn't father time tripping Federer and reminding him of his mortality. Maybe it was Federer's knee sending a warning, telling Federer he had been a bit hasty in returning.

"It's pretty incredible to see the progress I've been able to make in a short period of time," Federer told the ATP in late March, about seven weeks after his surgery. In his latest statement, a more sober Federer philosophically wrote, "The silver lining is that this experience has made me realize how lucky I have been throughout my career with very few injuries."

The one thing we've learned over the years is that there's no telling about longevity, about who will or won't have it. Despite this setback, Federer appears to be built for the long haul. He's as much in love with the game as it is in love with him. It looks as if he's just been denied a final shot at glory. He's found a greater project than two weeks in Rio.

"I am as motivated as ever and plan to put all my energy towards coming back strong, healthy and in shape to play attacking tennis in 2017," Federer wrote.

Curious that Federer chooses to insert the adjective "attacking." It's as if he's telling us: Don't expect to see some 35-year-old has-been hobbling around out there next year, punching up moon balls, either.

Get the signs and posters ready: Tokyo, 2020.