Manny Pacquiao will continue to challenge Errol Spence Jr. for the welterweight title in Las Vegas on Aug. 21.After a pre-fight medical examination revealed that a retinal tear was found in Spence's left eye, the Philippine senator will now face Yordenis Ugas from Cuba. The Nevada State Athletic Commission conducted the exam on Monday. Spence will have surgery in Dallas on Wednesday.Ugas, ESPN's number one boxer at 147 pounds, was scheduled to defend his title against Fabian Maidana in the PBC on Fox PPV chief-support bout. Ugas, ESPN's No. 6 boxer at 147lbs, was to defend his title against Fabian Maidana during the PBC on Fox PPV chief support bout. Sources told ESPN that Maidana had suffered an injury while sparring Monday night and had already pulled out of the Ugas fight. To make the pay-per-view telecast a four-bout affair, a fight will be added.Spence, who holds two titles at welterweight, said that he was disappointed not to be able fight Manny Pacquiao. "I was very excited about the fight. The doctors discovered a tear in my left side eye. They advised me to have surgery ASAP. I was unable to fight with that condition.Spence posted on Twitter Tuesday night, writing that he'd had three eye doctors examine him and that they were all positive about his recovery. Spence stated that he would return to face Pacquiao Ugas' winner "for certain."He wrote, "I came back to worse."Even worse, Spence (27-0; 21 KOs), was involved in an horrific one-car accident in October 2019, which resulted in Spence spending a long hospital stay.Spence, ESPN's No. 4 pound-for-4 boxer Spence returned one year later with a unanimous decision victory over Danny Garcia. This set up a career-defining fight against Pacquiao.Pacquiao's win over Ugas would not necessarily mean that he will fight Spence next. He is currently preparing to fight Rodrigo Duterte in the Philippines presidential race, so his next fight may be his last.The future Hall of Famer was trying to score one of the greatest over-40 wins in boxing history against Spence. The 42-year-old Pacquiao defeated Keith Thurman in July 2019, winning the WBA title. He has not fought since. The WBA acknowledged Ugas as its champion during that break, rejecting Pacquiao's July petition to be reinstated.Pacquiao, ESPN's No. 1 welterweight, stated that "the only way to win a world championship is in the ring." 3 welterweight. "... "...I ask you to pray for Errol Spence Jr.'s complete and prompt recovery. We are thankful that Errol Spence Jr. was able to be examined by a doctor and his eye condition was discovered before he sustained any more damage.Pacquiao (62-7-2; 39 KOs), is an expert on eye damage. In 2010, he beat Antonio Margarito, breaking his orbital bone and causing a detached retina in his right side.This win earned Pacquiao the title in the eighth division, which is the most important in boxing history. Pacquiao remains the champion more than ten years later. He'll now try to be champion against another formidable foe.Ugas, 35 years old, won bronze medal for Cuba in the 2008 Olympic Games. He also lost his title fight to Shawn Porter, in which he was controversially defeated.He now prepares for an even more difficult test and one that is completely unexpected.Ugas (26-4-12 KOs) said, "It's an honour to fight the great multi-division champion Manny Pacquiao. "I have a lot of respect for Pacquiao but I'm coming to win this fight.He said, "Everyone knows my story of how I came here to America to pursue my dreams of becoming world champion. Now it's my turn to stamp my legacy as one of the greatest Cuban fighters ever to put on a pair a gloves." "I love my country, and I want this fight to be dedicated to all those who are fighting for freedom."