Trainer: Cain Velasquez is not the greatest heavyweight of all time...yet

When Ultimate Fighting Championship (UFC) heavyweight kingpin Cain Velasquez was forced to bow out of his much-anticipated title fight against Fabricio Werdum due to injury (details), it put a huge dent on UFC's first-ever trip south of the border, as the fight was set to headline UFC 180 from Mexico City, Mexico, on Nov. 15, 2015.

But, let's take a step away from what the injury did to the promotion, and dissect how it affected Cain's mixed martial arts (MMA) career.

The bout was going to be his first since October of 2013, as Velasquez was forced to sit on the sidelines after knocking out Junior dos Santos at UFC 166 due to a shoulder injury and subsequent surgery. Now, his most recent injury (knee) will likely keep him on the bench until early 2015.

According to his head trainer at American Kickboxing Academy (AKA), Javier Mendez, it's because of the injuries -- not a lack of talent -- that Cain (13-1, 11-1 UFC) can't be labeled as the greatest heavyweight fighter of all time. Because had it not been for his setbacks, Velazquez would've earned that label long ago.

Mendez explained his comments on a recent edition of The MMA Hour:

"What I do think is this, had he never gotten injured, he'd be the greatest heavyweight of all time right now; because of what the guy can do. What I do believe, is that it will take longer for people to recognize him as the greatest, you know, because of the injuries. Even if he never gets injured going forward, you know depending on him, he has a good six, seven or maybe even 10 years ahead of fighting, if that is what he chooses to do. So, he is still going to hit that goal of the greatest of all time, but obviously we can't hit him with that label right now. Not yet. He needs more fights I think. But he will get there, it is just going to take a little longer."

Some even attributed his first and only loss to Junior dos Santos at UFC on FOX 1 to injury, as well, as the 265-pound king was going into the bout with a bum knee that prevented him from throwing any kicks.

And when you can only stick to the boxing aspect of MMA against one of the best boxers in the division, it spells trouble, according to Mendez.

The good news is, Cain underwent successful surgery to repair his knee. During the procedure, however, it was discovered that his MCL had suffered more damage than anticipated, which means his layoff will be a bit longer than expected.

Once he's ready and able, he'll be facing the winner of UFC 180's revamped headliner, Fabricio Werdum vs. Mark Hunt, on his road back to solidify himself as the GOAT.

Roy Nelson, though, seems to think Cain is chasing a title that doesn't exist.