Meanwhile, on July 20 in Iowa, Zhang, the 6-foot-6, 250-pound southpaw from Zhoukou, Henan province, will put his 18-0 record on the line against German trialhorse Eugen Buchmueller, who is 11-2 with eight stoppages.

Zhang's No 12 world ranking and 13 knockouts make him a potential challenger for unified world heavyweight champion Anthony Joshua of Britain, who scored an 11-5 victory over him in the quarterfinals at the 2012 London Olympics.

On the surface, this triumvirate of crossroad tangos looks easy to predict: Pacquiao should be severely tested, but emerge with a decision; Lyu probably won't embarrass himself, but has little hope of winning; Zhang, fighting for the first time in nearly a year, should add another KO notch to his belt－albeit against a vastly inferior opponent.

But what if it all goes sideways?

If Pacquiao loses, it's no big deal. He'll simply reinvent himself again and fight on. For Lyu and Zhang, it's much trickier.

Should Lyu get beat up and stopped by the heavy-fisted Canizales, he'll have to spend the next two years trying to prove he deserved the title shot. That means challenging top contenders－and risking additional lopsided beatings. But at age 24, he still has time.

Zhang, if he loses or looks bad en route to victory, doesn't have that luxury. He's 35, and his window of opportunity is rapidly closing. The guy they call "Big Bang" has to blow away Buchmueller, then immediately step up against much tougher opposition.

For all three, it's a roll of the dice at the crossroad.

And the crossroad can be the loneliest place in boxing.

The writer is a Canadian author and former professional boxing trainer.