Amir Khan was the leading candidate to face Manny Pacquiao until the names of Terence Crawford and Timothy Bradley Jr. came into the picture.

As everyone knows by now, Pacquiao will be facing Bradley for a third time, while Khan is close to possibly fighting Kell Brook.

And while all of those things may have been settled, there are some who still ponder on what could have been. That includes the possible outcome had the Pacquiao vs. Khan setto taken place.

Jeff Mayweather, the uncle of retired American boxer Floyd Mayweather Jr., believes that had the fight taken place. Khan would have been knocked out because of his chin. He calls Khan's chin "made of china" via BoxingScene.com, backing it up by the fact that he doesn't like how Khan reacts when his previous opponents landed clean punches to his head.

Mayweather points out Khan's last fight against Chris Algieri. While Khan did win that one via decision, he believed that it was a testament to such and was a tough one that British southpaw had to endure.

The observation somehow backs the earlier point raised by Pacquiao adviser Michael Koncz.

In a post made last September, Koncz wasn't exactly thrilled with Khan had he been chosen. He believes Khan lacked the punch and grabbed his opponents a lot. And seeing that he and Pacquiao were former sparring mates, Khan would likely know a lot on when Pacquiao would strike.

And if Pacquiao would outwit him, the consequences could be dire. It may turn out to be what many feel, a tough hit that could wobble Khan in the same way he did against Algieri as Mayweather pointed out.

All of these are moot and academic with both fighters ending up fighting different opponents. Should Khan's chin indeed be fragile, Brook will get a chance to prove that once their fight is finalized, hopefully by June 2016.