Former two-time UFC light heavyweight title challenger Anthony "Rumble" Johnson has added a fairly significant wrinkle to his long teased comeback by agreeing to terms with Bellator MMA on Wednesday, sources told CBS Sports. 

Johnson (22-6) hasn't competed in MMA since losing a 205-pound title rematch to Daniel Cormier at UFC 210 in 2017. He retired immediately after the fight before publicly announcing his intention to return to the sport in 2019.  

The 36-year-old's comeback, however, has been painstakingly slow for reasons that remain unclear. Johnson didn't enter the USADA testing pool to begin his mandatory six months of consistent clean testing before a UFC return could be cleared until last September. 

The news of Johnson mutually parting with UFC was first reported by ESPN's Ariel Helwani. "Rumble" is expected to debut with Bellator in early 2021 and do so as a light heavyweight where he had the majority of his success inside the Octagon. 

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Johnson, who has yet to sign a deal with Bellator but is expected to do so imminently, originally announced in 2019 his comeback could see him compete at both 205 pounds and at heavyweight, a division that he hasn't competed in since a one-off victory over Andrei Arlovski in 2013 under the now defunct World Series of Fighting banner. 

Originally competing as a welterweight, the 6-foot-2 Johnson turned pro in 2006 and made his UFC debut the following year. It didn't take long for Johnson to establish himself as one of the most devastating knockout threats in MMA history regardless of weight as he was able to carry his power with him to each weight class. 

Johnson's second stint with UFC, which began in 2014, was his most dominant. Despite a pair of defeats to Cormier in light heavyweight title bouts, Johnson went 6-2 overall with five knockouts including victories over division luminaries Phil Davis, Antonio Rogerio Nogueira, Alexander Gustafsson, Ryan Bader and Glover Teixeira.

Bader currently owns the Bellator heavyweight title and recently lost the 205-pound crown to rising upstart Vadim Nemkov. Johnson is expected to be an instant title contender at both divisions and his signing adds significant depth to a Bellator light heavyweight division which, in addition to Nemkov and Bader, includes Corey Anderson, Davis, Lyoto Machida, Liam McGeary and (occasionally) current middleweight champion Gegard Mousasi.

Johnson's departure from UFC comes at a time in which the promotion has come to terms on the release of a number of big-name fighters in 2020 still under contract including Anderson Silva, Yoel Romero and Corey Anderson.