Cited from Yahoo Sports by Loren Johnson:
5. Roy Jones Jr.
Roy Jones Jr. seemed invincible and unbeatable in his prime. He was one of the best fighters of his generation. It is debatable whether or not he had a fragile chin in his best years. But, Jones currently has a weak chin.
Jones has lost three fights by early stoppage. It has been rumored that he avoided power punchers because of his fragile chin. He never fought his main rival at light heavyweight Dariusz Michalczewski. Michalczewski was a hard hitting boxer that won 38 fights by knockout. Jones also never faced powerful punches such as Julian Jackson and Nigel Benn.
It may be because of Jones weak chin that he is reluctant to brawl. “I enjoy outthinking another man and outmaneuvering him. But, I still don’t like to fight,” said Roy Jones Jr.

Are you kidding me? Roy Jones does not have a glass jaw and doesn’t deserve to be even on that list.Jones is the most physically trained boxer of all time.Jones had a hell of a chin and the only reason he got knocked out was because he kept moving up and down weight classes. Enough of the whole essay about him woman! We both aren’t boxing experts so these are just “opinions”.