3 biggest storylines ahead of UFC 301

UFC 301 - and Steve Erceg's improbable opportunity to become a champion in his fourth Octagon bout - is upon us.

In Saturday's main event, Alexandre Pantoja defends the flyweight title for the second time against Erceg, the No. 10-ranked flyweight. In the co-main event, UFC Hall of Famer Jose Aldo comes out of retirement to face Jonathan Martinez in a high-stakes bantamweight tilt.

Here are three key storylines ahead of the UFC's return to Jeunesse Arena in Rio de Janeiro.

Erceg has a chance to massively shake up the flyweight division

Unless you're from Australia, you probably haven't known Erceg for more than a year.

Erceg has only been on the UFC roster since February 2023, after he impressed matchmaker Mick Maynard at a regional event in his hometown of Perth. For reference, that was one day before the first Islam Makhachev versus Alexander Volkanovski fight. Erceg made his short-notice debut four months later at UFC 289 in Vancouver, pulling off the upset against David Dvorak and immediately cracking into the top 15 at flyweight.

A decision against Alessandro Costa and a knockout over Matt Schnell in March have put Erceg on a rapid rise and cemented him as the most promising up-and-comer at 125 pounds.

Still, at 3-0 in the UFC and ranked No. 10 in the division, there seemed to be a large gap between Erceg and a title shot. That was until the UFC realized there weren't too many opponents to choose from for the champ's Brazilian homecoming, with Pantoja having recently defended the title against top contender Brandon Royval and Royval recently beating former champ Brandon Moreno. As unlikely as it was for Erceg - or essentially anyone - to get a crack at the belt in his fourth Octagon appearance, he's the best option.

Now, the relative newcomer to the UFC, affectionately known as "AstroBoy," has a chance to turn the flyweight division on its axis. Given how he performed in his first three UFC outings, don't be too shocked if Erceg marches into hostile territory and does exactly that.

Is Aldo coming back for another bantamweight title run? Or to get out of his contract?

There has been a lot of discussion in MMA circles about the reasoning behind Aldo's sudden UFC comeback. After all, the former featherweight champion seemed content in retirement - though his version of retirement meant competing in three boxing matches in five months - and, of course, had nothing else to prove.

Perhaps Aldo has gotten the MMA itch like so many retirees before him, and in his mind, a win over a rising bantamweight like Martinez puts him back in the title mix. But the more likely answer is that the "King of Rio" is returning for one reason and one reason only: to move on once and for all.

Aldo recently confirmed that he has one fight left on his UFC contract. That means the 37-year-old Brazilian will be a free agent after Saturday and won't need permission from the UFC to do whatever he wants in the combat sports world. Whether that's a boxing match on the Jake Paul versus Mike Tyson undercard in July, a tilt against Bellator champion Patricio "Pitbull" Freire, or something else, the world could be Aldo's oyster once he makes one more UFC walk this weekend.

Last dance for 'Lionheart'?

At age 35 - but seemingly 45 in fight years - former light heavyweight title challenger Anthony Smith has been nearing the end of the road for a while. Long gone is the guy who finished Rashad Evans, Mauricio "Shogun" Rua, and Volkan Oezdemir to reach a 2019 title shot against Jon Jones. Smith isn't the fighter anymore who impressively bounced back from a loss to Jones by submitting Alexander Gustafsson. A loser in three of his last four fights, the miles have finally caught up to "Lionheart."

Depending on how his main-card bout against undefeated prospect Vitor Petrino plays out, UFC 301 may mark the final walk to the Octagon of Smith's veteran career.

Despite being a budding MMA analyst for ESPN, Smith seems keen on continuing to fight for as long as he can, with the goal of becoming a champion still in the back of his mind. Understandably so, considering we've seen a handful of fighters seize the 205-pound throne in their mid-to-late 30s in recent years. But if Smith can't get past a far less experienced Petrino, who's 4-0 in the UFC, the fighter out of Omaha, Nebraska, will have to have an honest conversation with himself about whether it's still in his best interest to beat people up and get beat up for a living.