The two-time world titleholder from Doncaster says that the lack of a stellar opponent since defeating Julio Ceja for the IBF belt in 2013 has made it difficult to really get up for a fight.
But McDonnell says that will not be the case this time around, as he looks to set to face Kameda on either the 11th April in New York or the 18th, when he will potentially headline under the lights in Las Vegas.
He told Sky Sports: ???I lacked a bit of motivation in my last couple of fights, especially after I lost the IBF title and had to drop back down to eight or 10 rounds.
???I was meant to win the WBA against Tabtimdaeng Na Rachawat at Wembley, whilst the defence against Javier Chacon was the same as he wasn???t anything special, so I never really got going. But this time against Kameda there???s no worries about my motivation.
???He???s undefeated and meant to be the next superstar in Japan, so it is a great boost for my training to be fighting him. This fight is going to make a huge difference to my life, as it???s going to generate a lot of money for me and my family. It???s time to knuckle down now and really push on, starting with this fight and then onto even more massive unification fights.”
McDonnell also says that these are the fights he is in the sport for and has no interest in racking up ???meaningless??? defences that he is expected to win.
The Yorkshireman also has strong views on fellow British world titleholders Scott Quigg and Carl Frampton???s inability to seemingly tie up a deal for their domestic ???super-fight??? either in Manchester or Belfast.
???I???m only after the big fights now,??? he said. ???I???ve proven that I???m one of the best in the UK by winning the English, British, Commonwealth and European, where I racked up four defences. Then I had to get through a tough final eliminator and then went on to hold two world titles, defending one of them once.
???I???m sick of just racking up routine defences and padding my record out, I want those big fights. I???ll win this next fight and I???ll have the WBA and WBO, then I???m going to track down the WBC champion and take his belt.
???There???s no point pussy-footing around, is there? If you???ve got a world title belt, fight someone who has got one of the others and unify the division. I mean, for example, I don???t see any reason why Carl Frampton and Scott Quigg can???t get it on with their belts on the line.
???You???re both world champions and you want to prove that you???re the best in the division, so stop running away from each other and fight, it???s as simple as that. It???s not like they???re not going to get paid well, is it????