MacDonald is one of the most prestigious free-agency acquisitions in Bellator history. The Canadian welterweight signed a multi-fight deal last year, ending a six-year run with the UFC.
Although he's coming off back-to-back losses, MacDonald is considered one of the best welterweights in the world. He holds career wins over the UFC's current champion, Tyron Woodley, and its No. 1 contender, Demian Maia.
Bellator president Scott Coker has already announced the winner of Friday's fight will receive a title shot.
Here's everything you need to know about Bellator 179's main event on Friday, courtesy of ESPN's Cheat Sheets.
Rory MacDonald (18-4) vs. Paul Daley (39-14-2), Welterweight
Odds: MacDonald -310; Daley +255
Ahead of debut, MacDonald returns to roots, focused on strengths
Rory MacDonald has been training mixed martial arts long enough to know he'll never learn everything.
Earlier in his career, MacDonald was the poster boy of a "new breed" of fighters -- a generation that grew up on full MMA training, rather than a single discipline.
In 2010, MacDonald joined renowned Tristar MMA in Montreal, where his technical abilities flourished under head coach Firas Zahabi. For this camp, however, MacDonald returned to his roots in British Columbia, to train under former head coach Davis Lea.
"Tristar is a world-class gym, with people coming and going all the time," MacDonald said. "Firas is very diligent about staying in touch with the most up-to-date techniques and he's always got new stuff evolving and new guys coming through. Sometimes, it can just be a little overwhelming with all that new information.
"You want to be good at every aspect of MMA, but there are so many avenues in each discipline -- techniques, approaches, levels of aggression -- there are so many variables that it's hard to close yourself off from the noise and focus on your own strengths."
MacDonald will still have Zahabi in his corner, but says this camp has been very beneficial in rekindling his old style.
He didn't feel himself during his last performance, a five-round decision loss to Stephen Thompson last June. That fight proved to be MacDonald's final UFC appearance, as he signed with Bellator months later.
"I think I have an aggressive style in every aspect of MMA," MacDonald said. "I like to focus on coming forward and pressing the fight. I'm expecting a dominant, brutal fight on my behalf."
With retirement potentially on horizon, Daley eyes dream fights in near future
Paul Daley believes this fight will go down as one of the biggest of his career, which is saying something for a man with 55 career appearances.
Daley, 34, says he remembers the high expectations placed on MacDonald years ago. The kid was a phenom and groomed as "the next Georges St-Pierre." The future star of Canadian MMA. And even though MacDonald never won a UFC title, he represents a major challenge for Daley.
"He was the next big thing for a long time," Daley said. "He's been ranked highly in the world for a long time, and he was always seen as the second coming of St-Pierre. I did think he was part of a new breed in the fact he's always been well-rounded, but I was never really a fan of his. He's never captured my imagination. But he's definitely one of the first guys who came up as being very well rounded."
Daley also considers himself a well-rounded talent, even if his primary reputation centers around knockouts. As much as he looks forward to matching technique with someone like MacDonald, he also feels he doesn't have much left to prove.
Currently, Daley doesn't see himself fighting beyond age 35, which means he might only have another 18 months left. For Daley, that means a focus on big fights.
"I don't want to look up at that 'Tale of the Tape' and see the number 36," Daley said. "I think 35 is my retirement age, and I would love to fight the big names of my era, as you see in boxing. I'm fine fighting the younger guys, as I did with Brennan Ward earlier this year. But I'd prefer to fight some of the legends of my time.
"I'd definitely like a rematch against Douglas Lima for the belt, if he's the champ. Michael Page, although I hate to mention his name because I think he's gets too much air time, has called me out. That's two big fights. Benson Henderson is a guy who came across from the UFC, and even the 155-pound champion Michael Chandler has called me out.
"A rematch against [UFC welterweight] Nick Diaz would be awesome. That would be the one, more so than any other."
With MacDonald switching camps and talking about a return to his old form, you can't help but wonder how different his approach will be. He's not reinventing himself ... is he? Because the MacDonald we've come to know in recent years would match up pretty darn well with Daley.
MacDonald knows how to fight long. The comparisons to St-Pierre never truly fit, but an efficient jab is definitely something the two have in common. MacDonald is quite accurate with that lead left and has good extension to it. He has a strong repertoire of front and leg kicks, which could work wonders against a shorter opponent in Daley, who can be a bit heavy on his lead foot. He's also good at taking the center of the cage and walking opponents to the fence, which is not where Daley wants to be on Friday.
All of this suggests Daley needs to come forward. He can't match MacDonald on the outside, nor can he allow MacDonald to corner him against the fence. That means asserting himself as the aggressor, which he's capable of doing -- but he'll want to be careful about overdoing it and opening himself up for a takedown. MacDonald's wrestling typically doesn't dictate his contests, but it is a skill he possesses.
It's true, Daley has made recent comments about matching MacDonald's technical prowess, but the reality is that the more back-and-forth this fight is, the better it probably is for him. The bulk of his advantages lie in that midrange pocket, where he can put his hand speed and combinations to use and test MacDonald's notoriously shattered nose. The key lies in Daley's ability to get into that range on a regular basis against an intelligent, skillful opponent -- unless MacDonald truly has taken a completely different approach and intends to meet Daley in the middle and trade bombs.
Prediction: MacDonald decision