Derrick Lewis has his next assignment — and it’s a big one.

“The Black Beast” confirmed Monday on The MMA Hour that he is officially slated to fight former Bellator heavyweight champion Alexander Volkov on Oct. 6 in the co-main event of UFC 229, the blockbuster pay-per-view card headlined by the return of Conor McGregor against lightweight titleholder Khabib Nurmagomedov. ESPN first reported the bout.

The booking represents a fast turnaround for Lewis, a 33-year-old heavyweight contender who defeated Francis Ngannou last month at UFC 226. Back injuries have plagued Lewis throughout his Octagon run — even prompting “The Black Beast” to briefly retire from mixed martial arts in 2017 — and those issues unfortunately reared their ugly head again at UFC 226, contributing to a performance that many, Lewis included, felt was lackluster.

But Lewis is feeling better of late.

He revealed Monday on The MMA Hour that he underwent a new treatment on his back “two or three weeks ago” that has his body feeling up to the challenge of taking on another fight camp.

“Right now it’s going pretty good,” Lewis told host Luke Thomas on The MMA Hour. “The shots that I took, they said it should last like 10 to 12 months.

“It wasn’t stem cells or nothing like that. It was something — they shot me like 20 times in one spot, it was some type of steroids.”

Lewis noted that the procedure was approved by USADA. He explained that his back injuries are “muscular” in nature, and have nothing to do with issues regarding the discs in his back. In addition to the steroid shots, Lewis said he is currently doing “a lot of stretching and rehab” and has been told that trimming his weight down to the 250-pound range, rather than 285-pound range he’s walking around at now, would benefit him in the long run.

Overall, though, he’s encouraged by the progress he’s felt since UFC 226.

“This is my first time having them (the shots),” Lewis said. “I was taking magnesium, and magnesium was working for a while, but this last fight right here, it didn’t work at all.

“I feel good. I feel real mobile right now,” he added. “All of my fights, especially all of my UFC fights my whole career, I’ve never been in there without any kind of impingement and pain wrong with my back. It just amazes me that I made it this far with all the pain that I have to endure during all of my fights.

“We’re taking it step-by-step, day-by-day. We’re taking it real slow, because ain’t no way I’m going to pull out of this fight again. I’ve pulled out in the past and I ain’t planning on doing it for this fight here.”

If Lewis can make it to UFC 229 healthy, he faces a golden opportunity to cement himself as a top contender in the heavyweight division.

An untold number of eyes will be watching the pay-per-view card because of the allure of McGregor’s long-awaited return against Nurmagomedov, so for Lewis, a decisive performance against Volkov could go a long way in positioning him to challenge for the heavyweight title once Daniel Cormier vs. Brock Lesnar is settled in early 2019.

“He’s a tough guy, he’s a long guy,” Lewis said of Volkov. “I really can’t stay in his kicking range or his reach, and stuff like that. I believe I’ve gotta push the pace and get closer to him and really get more strikes off than he can land on me.

“Hopefully it can be a dominating performance and put me right back in the place I was supposed to be in — be a contender, a real contender, and be fighting for the belt next.”