Matthew Macklin feels now is the time for Anthony Joshua to hang up his gloves after his shock fifth-round knockout defeat to Daniel Dubois.
Joshua was aiming to become a three-time world champion by claiming the IBF world heavyweight title but instead suffered a damaging setback - the fourth of his career - after he was knocked out.
The 34-year-old was floored four times by Dubois at Wembley Stadium, including once in the first round, and many people have called for Joshua to retire afterwards - including Macklin.
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"He's 34 years of age. He's had a fantastic career, he's achieved beyond his wildest dreams with money that his grandchildren will live healthily off. What's left to prove? Everything is a weigh-up, everything is a risk. What has he got to gain when he's got so much to lose," Macklin told Sky Sports News.
"Boxing isn't like football where you can move into a different position or maybe drop down to a lower division to still enjoy playing. Boxing is brutal, it's dangerous, people get knocked out.
"I don't think AJ recovered from the first knockdown. I thought he was badly shaken even though he buzzed Dubois right at the end. He gets walks onto a shot going for the uppercut and gets caught wide open and Dubois catches him over the top with a short right hand.
"Retirement is a very difficult decision in boxing because it's down to you. In football, that decision is generally made for you. You just don't get picked for the team any more, so you kind of have to accept it, or you come down a division.
"You come down a division in boxing and start getting knocked out by people who you wouldn't fight previously. It's different, it's modern gladiatorial, it's brutal. There's a health factor as well.
"To me, AJ looked concussed from the first round on so these are things you have to look at."
Joshua released a video on X on Monday afternoon insisting his journey in boxing is not over yet, with Macklin taking to social media, saying: "If he was my brother I'd tell him to forget about boxing for a bit and then call a press conference to announce his retirement and celebrate an amazing career."
Macklin added on Sky Sports News: "It's 12 years ago since he won the gold medal in London. It goes downhill from here.
"Joshua is a proud man who won't feel comfortable watching that back. If he does choose to retire, we shouldn't be mourning his career. We should be celebrating it."
A changing of the guard moment?
Joshua is already looking at a potential rematch with Dubois as well as another all-British clash with Tyson Fury in the future.
And Macklin believes there is every chance Joshua could get past Dubois if there was to be another showdown.
"There's definitely a chance he could [win]," said Macklin, a former three-time world title challenger. "There's a decent chance, but I don't think it's probable. He was a solid favourite going in on Saturday night. Not many people picked Dubois. No one was putting their neck on the line picking Dubois.
"Dubois' confidence and belief will be high and a rematch will be much harder. It's a changing of the guard.
"For me, this was Dubois' [Wladimir] Klitschko moment and that's sport, that's boxing, the young hungry lion dethroning the great king."
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