Disagree vehemently. Roy Jones throughout his career showed absolutely no signs of a weak chin from his campaign from 160 all the way to Heavyweight. It is only after he came down from HW to LHW that his chin became a problem. Now if his case was unique I might give the theory that he was simply never exposed throughout his entire career credence but the same thing happened with Chris Byrd. Byrd has taken shots from David Tua, Wladimir Klitschko (the first bout), Vitaly Klitschko and to some extent Jameel McCline and has managed to not only win some of these fights but he managed to last the distance in some of the losses against pretty decent punchers. He's been in there with enough punchers at HW to suggest that he has a heavyweight grade chin. So when he made his ill-fated decision to go down to LHW and fight Shaun George who is an unheralded fighter with unremarkable power for that weight and he got knocked around the ring like a rag doll it suggest that his decision to move down in weight adversely affected his ability to take punches. The parallels are similar and IMO Roy Jones is a victim of his poor decision making. Not of a poor chin.