Jon Jones calls out WWE champion Brock Lesnar after knocking out Daniel Cormier

Lesnar announced his retirement after testing positive, which also meant he was out of the USADA testing pool.

Jon Jones returned to the Octagon after a year layoff to knock out Daniel Cormier to reclaim the light heavyweight championship. After the bout, Jones took the opportunity to tell Lesnar to come back and feel what it feels like to get his "ass" kicked by a fighter 40 pounds lighter.

Jones has won his last 14 consecutive fights.

While the UFC card in Madison Square Garden would be a grand spot for them to show down, Lesnar won't be eligible to return until December due to his USADA suspension stemming from his victory over Mark Hunt:

Earlier this week, rumors spread that Lesnar (5-3 MMA, 4-3 UFC) could face light heavyweight champion Jones upon his return. However, there are several factors that need to be addressed, according to The Wrestling Observer Newsletter's Dave Meltzer (subscription required).

"The working plan is for Brock Lesnar to face Jon Jones, provided Jones beats Daniel Cormier this week, with the idea of late December. But that time frame may not work since Vince McMahon would have to approve of any date until April. We were told that Lesnar vs. Jones was the working idea from a number of sources, but one said that it wouldn't happen that early and would have to be in 2018."

Jones previously discussed the possibility of facing Lesnar during a UFC Facebook chat this week. The former champion said he'd be interested in the fight, but wasn't confident it would happen.

"He's a massive dude," Jones said. "It would be a massive draw, really big for the sport. It would be a great challenge; that's a big old boy.

"I doubt Brock Lesnar would take that fight, though. I definitely wouldn't try to wrestle with him the whole time. I'm not going to tell you what I would do."

Lesnar responded during an interview with APNews.com on Wednesday, claiming he'd accept the challenge.

"Would I fight Jon Jones? Anytime, anywhere," Lesnar said. "Right now, he should be worried about 'DC' on Saturday night."

Last week, Meltzer reported last week that Lesnar had gotten back in the USADA testing pool for UFC.

However, Lesnar's UFC future is still a matter of speculation as he remains under contract with WWE until April 2018 and is currently serving a one-year suspension for two failed drug tests for Hydroxy-Clomihpene.

Lesnar was suspended after a July 9th test turned out to be positive and his one-year suspension was frozen in mid-February, which means it still has five months remaining and the former champion won't be able to compete again until mid-December.

Lesnar announced his retirement after testing positive, which also meant he was out of the USADA testing pool.

According to Meltzer, the rumors of Lesnar and Heyman visiting UFC's offices were denied by sources, however, those within UFC did confirm interest in Lesnar making a return to the octagon.