The preeminent Grand Tour rider of any moment feels invulnerable, unbeatable. Until, quite suddenly, he loses.

Chris Froome turns 33 on Stage 15 of the 2018 Giro d’Italia — coincidentally one of the toughest stages of the race. He announced in a video message Wednesday that he will race the Italian tour for the first time since 2010. He wants to win the first Giro-Tour double since Marco Pantani, in 1998.

He won’t. And because of this attempt, it’s possible he’ll never win another Tour.

That would be a shame, really. He’s so close to five — to that rarefied air, occupied only by Anquetil, Merckx, Hinault, and Indurain. (Another rider won seven Tours, but then he didn’t.) It’s the ultimate legacy, and to give it up for a shot at a less-prestigious prize, well, I don’t understand it.

Greed or hubris. It must be one of the two.

There are rumors — reports, even — of a 2 million euro start fee that would land with a soft thud in Froome’s already-full bank account. But would a man who already has millions risk a five-Tour win legacy for two million more?

There’s greed.

Perhaps Froome wants to win four Grand Tours in a row (Tour, Vuelta, Giro, Tour). Maybe he fancies himself a modern day Pantani, and wants to match Il Pirata’s Giro-Tour double of 1998 — a feat accomplished during what is believed (hoped) to have taken place during a different, darker era. Maybe Froome believes so firmly that he and his Sky team, and they alone, have what it takes. Maybe he has seen the recent “double” attempts, and failures, of Quintana and Contador, and believes they don’t apply to him. Maybe he is willing to risk the sport’s biggest prize, that five-win legacy, for a pink jersey, because he believes he can have both.

There’s hubris.

Froome is not young, not anymore. He became a Grand Tour contender relatively late, at age 27, and though he may feel unassailable today, fresh off back-to-back Grand Tour victories, he, too, will go the way of the legends before him. His dominance will fade, superseded by talents younger and faster.

Froome will enter the 2018 Giro as the odds-on favorite. He’ll win it. The field will be weak, for one. As of Wednesday, other Grand Tour contenders smell blood in French waters. They will flock to the first Tour in years that Froome enters without ideal preparation.

In France, Froome will be tired. He’ll be vulnerable, and up against the strongest and most rested Tour field he’s ever faced: An ascendent Tom Dumoulin. A fresh Nairo Quintana. A young Romain Bardet. A wily Rigoberto Uran. They will be ready and waiting for the slightest falter.

Each season Froome shuffles closer to his athletic ending. He doesn’t know where or when it will be found any more than we do. But it’s there. In 2019, still with four Tour wins in his pocket, he’ll be 34. The average age of a Tour de France winner is 28. There are plenty of 33- and 34-year-old winners, but then something seems to happen. Indurain’s run ended at 34; Hinault’s at 31; Merckx’s at 29. There are no winners aged 35, and just a single man of 36 — that was Firmin Lambot, back in 1922. The Tour was quite different then.

Tired from the Giro, Froome won’t win this year’s Tour de France. It will be a year wasted in the quest for five Tours. He doesn’t have many years to waste.

It’s a bold decision. Admirable, even. But it could have consequences. Froome’s decision to take on the double this year, of all years, as he stands on the precipice of a legacy matched by four men in history, can only be explained as greed or hubris.

I don’t think it’s greed.