A loss to the WBA super middleweight champion Rocky Fielding not only could taint Canelo Alvarez's decision over Gennady Golovkin this year, it could significantly muddle the future for the Mexican star.
Alvarez moves up from 160 pounds to 168 in search of a third division title, which would place him in special company among his countrymen - only eight others have held three division crowns. That's the quest at Madison Square Garden against Fielding, a heavy underdog despite owning the belt.
As for moving up in weight but down in class - no one is comparing England's Fielding (27-1, 15 knockouts) to Golovkin - Alvarez insists there are no worries. He's not going to be looking ahead to his 2019 schedule just yet.
"I never like to get overconfident, whether I am the favorite or not," said Alvarez, who is 50-1-2, the only defeat to Floyd Mayweather five years ago, when Alvarez wasn't quite ready for such a master boxer. "To me it is not important who is favored. For boxing, one punch can change everything; anything can happen in the ring. I get my confidence in training for what I can do in the ring."
What he can do in the ring is punch with power, defend with elan, attack quickly or stealthily. It's not likely that Fielding, making his first title defense, has seen anything like Canelo in the ring.
But Alvarez is going from middleweight to super middleweight, which can be dicey.
"That's the risk, to be moving up in weight, to fight somebody who is used to fighting stronger fighters, who is used to taking stronger punches," Alvarez said. "I know the challenge, but I like the challenge, and I am happy for it."
Inevitably, Alvarez gets asked about a third bout with Golovkin, considering how close their previous two fights were, and the money and attention that would be there. He doesn't exactly shrug when questioned about it, but it's clear Triple G is not foremost on his mind.
"It is no secret we want to win this fight and then come back to our division, 160 pounds," he said. "But we can make combinations between 160 and 168. We will see what the future has ... but I can guarantee we will go back to 160 pounds.
"We had two good fights ... maybe in 2019 we can have a third fight. We'll see. Right now, I am 100 percent focused on Saturday. What I do know is I will fight in May and September next year. What I will do is give great fights to the public."