Ward faces a big step up in class when he defends his WBC international super-featherweight title against the experienced Nicaraguan after landing the title by beating Maxi Hughes in April.
???These fights are exactly what I need and exactly what I wanted at this stage of my career,??? said Ward.
???A former world title challenger is going to bring the best out in me and I???m in for a tough night in Hull, but I???m relishing the opportunity to test myself at this level.
???I???m really up for this fight next Saturday ??? I???m confident I???ll get the win and look great doing it.???
Ward is unbeaten in 13 fights and the 24-year-old from Leeds is confident he has all the tools required to one day become a truly world-class fighter.
???Once I get this fight out of the way, I feel I???ve got much more to learn and develop before I???m the finished article,??? he said.
???I???m in the gym training alongside a two-time world champion in Ricky Burns and a world-title challenger in Kevin Mitchell ??? I???m learning all the time from these guys.
???I???ve moved down from lightweight and to be truthful I wasn???t doing a great deal of dieting at the weight ??? I just lacked that little bit of man strength.
???I???ve been at super-featherweight for about a year now and my body has adapted to it well, I???m a big strong super-featherweight and I???m confident I could beat anyone in this division.???
Ward???s clash with Diaz is part of a massive night of action in Hull headlined by the all-Hull WBC world lightweight title eliminator between Luke Campbell and Tommy Coyle.
Former world title challenger Brian Rose faces a rematch with American danger man Carson Jones, while Ricky Burns and unbeaten Brixton heavyweight Dillian Whyte are also in action.