Oscar De La Hoya says it would be huge for Canelo Alvarez to knock out Shane Mosley on May 5, when the two meet for Alvarez's WBC junior middleweight title on the Mayweather vs Cotto undercard, but that he'd be "pleasantly surprised" if the 21-year-old Mexican star were able to pull it off. From Keith Idec at BoxingScene.com:
"Obviously, it would catapult him to another stratosphere. Nobody has ever been able to knock out Shane Mosley, including myself, including the best in the world. And if a 21-year-old fighter named ‘Canelo’ can do it, then that’ll be huge."
Mosley (46-7-1, 39 KO) has had a pretty awful stretch of fights recently, going 0-2-1 in bad losses to Floyd Mayweather and Manny Pacquiao, plus a butt ugly draw against Sergio Mora, and at this point hasn't won a fight in over three years. But he's never been stopped, and never seemed close to more than a corner stoppage or perhaps a referee deciding enough was enough in either of the Pacquiao or Mayweather fights.
Would Alvarez stopping him mean something? Sure, it would mean something, but it wouldn't mean a lot if on the night, Mosley is clearly more shot than ever and simply can't hang anymore. It does matter how Mosley actually performs. Not to boxing promoters, because their job is to sell lies and tenth-truths, but in reality it won't mean a LOT if Alvarez pummels a Mosley who simply can't do anything. It wouldn't mean much more than Alvarez stopping Carlos Baldomir (which Oscar counts as a big deal, even though it really isn't).
Golden Boy booked this fight because they don't think Mosley, who is closing in on 41 and has looked his age recently, can win the fight. They didn't book this to truly test Alvarez. I'm sure they're hoping for the stoppage, so that they can say that young Canelo did what Floyd, Manny, Oscar, Cotto, Vargas, Wright, and Forrest could not do. Canelo isn't fighting the Mosley those guys fought, except maybe Manny, but those are details that get left out of marketing campaigns.