Shane Mosley Jr. has spent the majority of his career vying for a world title opportunity. He’s taken big fights against contenders like Daniel Jacobs and Jesus Ramos Jr., but he hasn’t been able to get over the hump. Following a tough decision loss to Ramos Jr., Mosley Jr. is starting a new chapter in his boxing career, one that will bring high-profile headliners, beginning Sunday night at Zuffa Boxing 6. The 160-pound contender will face Serhii Bohachuk, a hard-hitting middleweight contender known for his volume and pressure. The challenge won’t be easy, with Mosley Jr. coming into the fight as a +220 underdog. KO on SI spoke to the contender about his path to joining Zuffa Boxing and what he expects from the fight on Sunday night. KO on SI : Why did you decide to join Zuffa Boxing and how is it different than other promotions you’ve worked with in the past? Shane Mosley Jr : "I got the call from them a couple of days after my last fight, where I lost to Jose Ramos in a decision.…