Breaking down Manny Pacquiao vs. Yordenis Ugas

LAS VEGAS — Two weeks ago, Manny Pacquiao was preparing to fight Errol Spence Jr., the unbeaten unified welterweight champion and perhaps the biggest test of his career since he fought Floyd Mayweather in 2015.

Spence is left-handed, as is Pacquiao. And because southpaws don’t often face other southpaws, that was a focus in training for the 42-year-old senator from the Philippines.

But 12 days before the fight, an ophthalmologic examination revealed that Spence had a detached retina and would need surgery that would prevent him from fighting Pacquiao on Saturday at T-Mobile Arena.

So Yordenis Ugas, who was supposed to fight in the co-main event, stepped in to take the fight. He, though, is…