Former four division world champion Roy Jones Jr. knows a lot about moving up in weight.

Jones captured his first world title at middleweight, then super middleweight, became unified at light heavyweight - and then in 2003 made history by jumping all the way to heavyweight to win a twelve round decision over John Ruiz to capture the WBA world title.

Jones was an interested observer earlier this month, when Saul 'Canelo' Alvarez returned to light heavyweight and was outboxed over twelve rounds by WBA world champion Dmitry Bivol.

Canelo captured his first world title at junior middleweight. He then became a unified champion at middleweight and last year became the undisputed champion at super middleweight.

Back in 2019, Canelo already tested the waters at 175 - when he jumped up to score a knockout of Sergey Kovalev for the WBO belt. Canelo would then drop down to 168.

Despite Kovalev being past his best, Canelo still had his share of issues in the fight and it was very close on the official cards when he scored the knockout in the eleventh.

Canelo received criticism from certain observers, who saw no reason for a ring return at 175 - against an undefeated champion in the prime of his career.

Jones believes the criticism was warranted.

"I would say yes he deserved the criticism and I only he say he deserves the criticism because you already went to 175, you beat Kovalev, what are you going back to 175 for? Are you trying to stay at 175, it’s obvious you’re not big enough to stay at 175, this is not the weight class for you, are you doing this to win titles? You’ve already been there, done that, why do you keep going back?," Jones told The DAZN Boxing Show.

When Jones defeated Ruiz for the heavyweight title, he would later drop back to 175 and never fought at heavyweight again. Jones realized right away that he was too small to compete at heavyweight.

"When I won the heavyweight title, I had one request - if Mike Tyson doesn’t want to fight, I’m not staying at heavyweight, I’m not big enough to be fighting these guys. What I got back from Mike Tyson was he’s done with boxing at the time, he doesn’t want to fight. I went back to light heavyweight and fought Tarver. I was not going to keep going back and forth to the heavyweight division, I’m not a legitimate heavyweight, I know this," Jones said.