Tim Tszyu’s fall from heavily favored to stand as a unified junior middleweight champion against a replacement opponent to a man indefinitely sidelined by a nasty head cut that this week forced his withdrawal from an Aug. 3 bout with Vergil Ortiz Jr. is a significant cautionary tale.

The Australian son of former world champion Kostya Tszyu, Tim Tszyu (24-1, 17 KOs) has banked on his warrior mentality throughout, and throughout he has been let down by those who could have better protected him.

Firstly, the fact the grisly cut he suffered by banging his head into the sharpened elbow tip of challenger Sebastian Fundora occurred so early in their March 30 Las Vegas bout that the ringside doctor could have easily intervened and halted the bout – sparing it for another day.

Tszyu did himself no favors, of course, by telling the referee and his corner that he could see through the cascade of blood that was rushing across his eyes.

But that corner also could have argued far more heatedly that enough was enough, saving their fighter from the 12 rounds of sustained damage he took on the injury that defused his effort and helped Fundora claim a split decision upset in what was the first Amazon Prime Video card for Premier Boxing Champions.

Worse than that, his management neglected to craft a rematch clause in the Fundora contract, freeing the Californian to pursue a lucrative October date against former welterweight champion Errol Spence Jr. at AT&T Stadium while the beltless Tszyu was sent to the demanding Aug. 3 assignment against Texas’ Ortiz (21-0, 21 KOs).

Tszyu withdrew from the bout this week, acknowledging his head wound hadn’t healed enough to allow for sparring.

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“I blame the freakin’ Las Vegas doctor … [Tszyu] had to finish 12 rounds with a hemorrhage on his head,” former welterweight titleholder Paulie Malignaggi said on Friday’s episode of ProBox TV’s “Deep Waters.”

The inattention to the long game of Tszyu’s career has indeed been hurtful.

“Training to book this [Ortiz] fight so fast was a mistake,” former 140-pound champion Timothy Bradley Jr. said on “Deep Waters.” “I don’t blame Tim. Tim’s a warrior. He’d fight with one arm.

“You dangle a fight of this magnitude, he’s going to take it. But his team needs to look out for him: ‘Look, man, you’ve got a really bad cut. …’ A little slice takes 100 days of no contact to heal. That [head cut] was deep, open for multiple rounds and constantly getting hit, getting worse. They should’ve been a little bit smarter.”

So now, Ortiz will move on to a new opponent, with Saudi Arabia’s Turki Alalshikh promising an “upgrade” on the card and Ortiz trainer Robert Garcia saying he’s preparing for the replacement fighter to be Ukraine’s WBC interim junior middleweight champion Serhii Bohachuk.

Meanwhile, Tszyu stays sidelined by the cut.

Tszyu-Ortiz could have been a rarity by today’s boxing standards, “a superfight they wouldn’t let marinate. … What is this, the ‘70s or ‘80s?” Malignaggi cracked. “They just go? Of course not.

“It was too good to be true.”