Former tennis world number one Andre Agassi hobbles tearfully out of the French Open, possibly for the last time. Six-times Tour de France winner Lance Armstrong says July's race will be his farewell.
Time catches up with every sportsman, no matter how great or how dominant.
Formula One champion Michael Schumacher, still without a victory in six races this season and with his hopes of an eighth title looking increasingly forlorn, knows that as well as anyone.
However tempting it may be to add the Ferrari ace's name to the list of sporting icons passing the baton to younger and hungrier opponents after years of supremacy, it would be unwise to do so just yet.
Even if his hopes of a sixth successive championship are fading, with just 12 points on the board compared to championship leader Fernando Alonso's 49, the 36-year-old German is not giving up.
The 'Red Baron' can take encouragement from the reds of Liverpool on that.
"I'm a fighter, I always try my best, right up until the end," said Schumacher before this weekend's European Grand Prix at the Nuerburgring, the closest circuit to his boyhood home near Cologne.
"If you look at soccer, a game has 90 minutes and often the direction it is going in may change even in the last few minutes or during extra time."
Wednesday's Champions League final, with underdogs Liverpool overturning a 3-0 half-time deficit against AC Milan to win on penalties in one of European soccer's greatest comebacks, reinforced that point.
"Quite clearly, yesterday shows as well that you have to fight to the last moment," Schumacher said.
MONACO DISAPPOINTMENT
Last weekend's Monaco Grand Prix was a disappointment for Schumacher, who finished seventh, yet it was also an affirmation.
The manner in which he sliced past Brazilian team mate Rubens Barrichello on the final lap and almost collided with younger brother Ralf at the line in a desperate bid to seize sixth place suggested that he has lost none of his hunger and determination.
"I am a full-blooded racer," he said afterwards. "We are not on a Sunday outing."
The Nuerburgring could well hand McLaren's Kimi Raikkonen a third win in a row on Sunday but it could equally herald Schumacher's return.
His rivals have certainly not written him off.
"I think it is clear to everyone that it has more to do with the tyres than anything else," said Red Bull's David Coulthard in Monaco.
"I don't think he is losing his edge."
The German is now the oldest driver, having made his debut in Belgium in 1991 when Renault's Alonso had only just celebrated his 10th birthday.
His opponents on the starting grid in that race included champions such as Alain Prost, Ayrton Senna, Nelson Piquet and Nigel Mansell.
Motor racing, despite the effects of G-forces and the rigours of fitness regimes, does not have the gruelling grind of cycling or the burn-out of tennis. Mansell was 39 when he won his title in 1992, Damon Hill 36 in 1996.
Schumacher is one of the fittest drivers and the message that comes through loud and clear whenever he is asked about the future is that he is enjoying himself as much as ever.
"Even a race like Monaco, I have to say I did enjoy it," he said on Thursday. "It was a tough time, I was at the back and I had to fight my way back into position."
TODT HOPES
Those who argued that Schumacher, with more than enough money in the bank and two young children, would head off into the sunset as soon as he stopped winning may find he is around for some time yet.
"If he doesn't win the title this season, then he will be even more motivated next year," said Formula One supremo Bernie Ecclestone last week.
Ferrari, publicly at least, are not yet ruling out success this year.
"Of course we have hope," said Ferrari boss Jean Todt. "We are working hard to get back to where we were last year. If it will be enough or not remains to be seen.
"It is still possible, difficult but there are still 13 races to go and so many things can happen.
"Let's say the others are quite well ahead but if you take two Grands Prix back, everything was focused on one driver [Alonso]. Then you had Raikkonen, who has won the two last Grands Prix and immediately things have changed.
"So let's hope we are the ones to win the next two Grands Prix."
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