The former WBO world champion has fallen to seventh in the ratings produced by the self-proclaimed 'Bible of Boxing', with Britons Anthony Joshua and Tyson Fury filling the top two spots, followed by American Deontay Wilder.
Cuban Luis Ortiz, American Dillian Whyte and Russian Alexander Povetkin round out the top six, with Parker next.
"If that's how they rank it, then of course, I don't have much to say about that," Parker told RadioLIVE's Sunday Sport. "It's highly respected.
