Speaking to The MMA Hour on Monday, Rothwell asserted that Velasquez could face a problem when the UFC's new drug testing policy comes into play on July 1. The policy involves more frequent, unannounced tests, making it even harder for fighters to take illegal substances without getting caught.
Rothwell said that he believes Velasquez will be effected by this, indicating that he believes that the UFC Heavyweight Champion is using PEDs.
"Let's see what happens after July 1, when the advance testing starts kicking in," Rothwell said.
"Let's see if [Velasquez is] still fighting the same way he has. I doubt it. I'm not implying anything, what I'm just saying, I don't believe every division is going to look the same after July 1st. If anyone takes offense to that, maybe they ought to look at themselves and look at their problems."
Talking to the media ahead of UFC 188 on Saturday, Velasquez rubbished Rothwell's allegations.
"Yeah, definitely it is [odd]," he said. "Not being a guy who's known for his physique, known for not being on anything. I've been tested before numerous times, before and after all my fights the day of."
The 32-year-old asserted that Rothwell was just trying to manufacture headlines, as he had done after his victory over Matt Mitrione on Saturday where his post-fight speech appeared to be very scripted and included an attempt at a hair-raising laugh at its conclusion.
"Watch his after-fight speech and you can find out where he's coming from," Velasquez added.