Two-time UFC Heavyweight champion Cain Velasquez is out of the UFC 196 main event due to a back injury. UFC President Dana White made the announcement on Twitter and current champion Fabricio Werdum will now be defending his belt against Stipe Miocic on Feb. 6.

Velasquez revealed in a Facebook post on Sunday that he was dealing with a sciatic nerve injury throughout his training camp. He apologized to Werdum and insisted that the injury was not an excuse, but he would rather perform in front of fans at 100 percent capability.

"All of us fighters have all fought injured at one time or another, but I can't ignore this injury, as my doctor has indicated that not addressing the problems with my sciatic nerve could have longer-term consequences. My fans deserve to see me compete as close to 100 [percent] as possible. I'm committed to giving them that," Velasquez wrote.

"Fabricio, I hope that you accept my sincere apology. I understand how you may think this is an excuse. I greatly respect you as a fighter and man, and we will meet soon," he added.

According to MMA Junkie, Velasquez is no stranger to injuries as he has only fought once in the past 27 months due to shoulder and knee injuries. He last fought in June at UFC 188 in his home country of Mexico, losing his title to Werdum via second round submission.

As for Miocic, it is a great opportunity for the 33-year-old veteran who defeated Andrei Arlovski in just 54 seconds at UFC 195 last Jan. 2. He has been in the hunt for a title shot, losing only twice in his UFC career.

Bleacher Report noted that Miocic has a solid wrestling background and good technical boxing skills, but his lack of name recognition among casual UFC fans hindered his rise to the top. The report added that Alistair Overeem was supposed to get the next title shot, but his contract with the UFC expired in his last fight back in December against Junior dos Santos.

Overeem was the last fighter to defeat Werdum back in 2011, who has a six-fight winning streak since then. Werdum earned a shot against Velasquez when he defeated Mark Hunt last November 2014 in an interim title match at UFC 180.

The Brazilian heavyweight has won nine of his last 10 fights and is currently ranked number 10 in the pound-for-pound rankings by Sherdog. Werdum will defend his heavyweight championship against Stipe Miocic in the main event of UFC 196 on Feb. 6, 2016 in Las Vegas, Nevada.