This article is part of our MMA Barometer series.

After a three-week layoff, the UFC returns with UFC 224 on Saturday in Rio de Janeiro, Brazil. This is the first of five-straight weekends with UFC fight cards. The card holds some potentially electrifying matchups, including a fight between UFC legends Lyoto Machida and Vitor Belfort, a potential title eliminator between Kelvin Gastelum and Ronaldo "Jacare" Souza, and a UFC Women's Bantamweight title fight between champion Amanda Nunes and challenger Raquel Pennington. All three fights feature at least one Brazilian, so the crowd should be in their typical raucous mood in support of their countrymen and women.

The dark horse Fight of the Night may be the main card bantamweight contest between John Lineker and Brian Kelleher. Both fighters are willing to stand and trade, and this fight has the makings of a matchup that earns both men $50,000 bonuses. Kelleher even acknowledged this on Twitter where he posted, "If you're one of those people shi**ing [on] this ppv do yourself a favor and watch me and Lineker fight, then go enjoy the rest of your night. You'll be glad you did." This fight is likely to feature a lot of significant strikes, and based on the durability of both fighters, should go into the later rounds. Neither fighter has been finished via KO/TKO in their professional mixed martial arts careers. Either fighter would be a strong pick for a DFS lineup based on striking volume alone, though the edge goes to Lineker ($9,000), who has five wins via KO/TKO in his UFC career.

Without further delay, here are our risers and fallers heading into UFC 224 and beyond...

Nunes looks to defend her UFC Women's Bantamweight title for the third time this weekend at UFC 224 against Raquel Pennington. Nunes has only one loss in her UFC career. She has good power in her hands and holds a black belt in Brazilian Jiu-Jitsu. The 29-year-old is known for finishing fights quickly, as six of her eight UFC victories have ended in the first round. However, her opponent this weekend has only been finished once in her professional mixed martial arts career, a defeat which came via submission.

This fight is interesting based on Pennington's durability. She has gone the distance with the likes of Bethe Correia and Holly Holm, two fighters known for their striking power. However, Nunes is a whole different animal. She has quicker strikes and holds a brown belt in Judo so she can take the fight to the floor if she is not having success standing. The only red flag for Nunes in this fight is potentially cardio, though those concerns have been alleviated of late. Nunes showed she can gas out in her lone UFC loss to Cat Zingano. However, it seems as if she ha remedied her cardio issues as she went five rounds with Valentina Shevchenko in her last title defense. If Nunes has her cardio in order, she should be able to come away with a victory on Saturday.

If Nunes does come out on top this could be a precursor to a long-awaited showdown with Cris "Cyborg" Santos. Prior to the current title defense, it was rumored Nunes would be moving up to featherweight to challenge the frightening champion. Nunes opted to defend her title again, but with a lack of legitimate challengers at featherweight it would only make sense for Nunes to move up in weight to attempt to dethrone "Cyborg." That would be an intriguing matchup, as no fighter has been able to come close to defeating Santos since she came to the UFC. Nunes may be the only fighter in the promotion who has the speed and power to matchup with "Cyborg."

Next Fight: Raquel Pennington, UFC 224: Nunes vs. Pennington (May 12th, 2018)

Isreel Adesanya, UFC, Middleweight

"The Last Stylebender" is a perfect 2-0 thus far in his UFC career and 13-0 overall. He has the makings of a future star with his length and striking. His octagon debut against Rob Wilkinson showcased his takedown defense and ability to get back to his feet. Wilkinson's strategy was obviously to close the distance and not fight at range, where Adesanya is at his best. Wilkinson was able to achieve three takedowns, but Adesanya almost immediately got back to his feet on each occasion. When the fight was at range, the Nigerian-born fighter showcased his striking skills. He broke Wilkinson's nose and kept the pressure on to the point Wilknson could only cover up in order to avoid further damage. The end of the fight came in the second round when the American fighter could take no more punishment and crumpled to the canvas.

Adesanya showcased great stand-up and respectable grappling in his Octagon debut. However, in his second fight it was shown he was somewhat vulnerable to takedowns. He did not show a great ability to get back to his feet when Marvin Vettori took him to the ground. His technique was suspect when he was on the bottom and he struggled to get separation in the third round of that fight to get back to his feet.

It is clear that the majority of his opponents will employ the same strategy used early on by Wilkinson and later in his fight with Vettori. The blueprint to a victory over "The Last Stylebender" seems to be to close the distance, stay chest to chest, and not allow him to employ his creative striking. Once the fight is on the ground, a dominant grappler should be able to smother the less-experienced fighter and not allow him to get back to his feet. However, nobody has been able to solve the puzzle of Adesanya as he is currently undefeated.

Hopefully he will continue to evolve and work on his grappling in order to nullify the strategy of grapplers. If he is able to consistently get back to his feet he will be able to employ his striking and pick apart his opponent. In his fight with Wilkinson he showed a great jab, which led to the Wilkinson's broken nose. If he is able to utilize his length and stay behind his jab, it will be difficult for opponents to get inside for a takedown.

Adesanya will be thrown into the fire in his next fight, as he squares off with No. 10-ranked UFC middleweight Brad Tavares. Tavares is a veteran that is well-rounded. Tavares prefers striking, but will likely test Adesanya in all areas. If Tavares keeps it a strictly striking match it could be a long (or short) night for the UFC veteran. A win over a top ten fighter will skyrocket the Nigerian up the UFC rankings.

Next Fight: TBA

Antonio Carlos Junior, UFC, Middleweight

Antonio Carlos Junior is currently riding a five-fight winning streak. His latest victory was an impressive submission victory over tough veteran Tim Boetsch. "Shoeface" looked good striking, and eventually worked for a takedown late in the first round and was able to sink in a rear-naked choke on Boetsch. Junior is a high level Brazilian Jiu-Jitsu black belt and is a world and Pan American Champion in Brazilian Jiu-Jitsu. Five of his seven UFC victories have come via submission, and Junior is a tall task for any UFC middleweight if the fight goes to the ground. He is currently the No. 13-ranked UFC middleweight, and will look to move into the title conversation in his next fight.

An interesting matchup for Junior in his next fight would be former World Series of Fighting champion David Branch. Branch is the No. 8-ranked UFC middleweight and his coming off a first round victory over the surging Thiago Santos on April 21. That improved Branch's record to 2-1 since his return to the octagon, with his loss coming to former UFC middleweight champion Luke Rockhold. Branch has power in his hands, and much like the Brazilian, is a decorated BJJ black belt. Junior has shown throughout his UFC career that he is adept in the stand-up realm and is an extremely dangerous fighter on the ground. L

ooking at his recent Octagon performances, Branch showed that he could be broken on the ground when he tapped to strikes against Rockhold. That is not a good sign as "Shoeface" has won all five finishes in the UFC via rear-naked choke. If he got Branch's back it could be a situation where the former WSOF champion gives up his neck for the finish. Branch is a good test in all areas for Junior, and a victory over the veteran would immediately vault the Brazilian into the title picture.

Next Fight: TBA

Rockhold has lost two of his last three fights. His last fight was for the UFC interim middleweight championship against Yoel Romero. Romero missed weight prior to the fight. In that contest, Rockhold was defeated via knockout in the third round. It seemed that Rockhold was once again moved to the back of the line in the title picture, but he decided to move up a weight class and now all signs point to Rockhold challenging for another interim UFC title, this time at light heavyweight. The UFC has reportedly been attempting to finalize a deal that would see the former UFC middleweight champion square off with former light heavyweight title challenger Alexander Gustafsson. The winner of that fight would face UFC light heavyweight champion Daniel Cormier following his matchup with UFC heavyweight champion Stipe Miocic.

This fight does not make sense on many levels. First, Rockhold is coming off a loss, and as mentioned above, has lost two of his last three fights. Second, if Rockhold is to win he will likely not agree to fight Daniel Cormier for the true UFC light heavyweight championship. Rockhold and Cormier are teammates at American Kickboxing Academy in San Jose, California and Cormier has similar arrangements with teammate Cain Valasquez. It is hard to imagine Rockhold would decide to fight his team captain after they have trained together for over ten years.

With respect to the fight against Gustafsson, it is a terrible matchup for Rockhold. Gustafsson is a long fighter, standing at 6-foot-5 with a reach of 79 inches. "The Mauler" is a big light heavyweight and his reach and size could cause problems for Rockhold, who is moving up a weight class. Gustafsson also has excellent boxing and rarely gets taken down. Rockhold has good stand-up, but Gustafsson was able to stand and trade with Jon Jones for five rounds. Rockhold is an excellent grappler, but Gustafsson's takedown defense has improved so much as of late it is hard to imagine Rockhold getting him to the ground. The Swede had great success in defending takedowns in his title fights against the aforementioned Jones and Cormier, two of the best takedown artists in the sport. Gustafsson was only taken down once in each fight. If the fight comes to fruition, it will be a difficult test for Rockhold. If he gets beaten soundly in that fight, his options will be limited if he wants to compete for a championship.

Gustafsson, Cormier and Jones are far above the rest of the division, and if he cannot compete with those fighters he will not be in the title picture. His only option would be to drop back down to middleweight to try to put himself back in the title picture in that division. A fight with Gustafsson will have huge implications on the remainder of Rockhold's mixed martial arts career.

Next Fight: TBA

Ever since his thrilling victory over Doo Ho Choi in the 2016 Fight of the Year, Cub Swanson has had a difficult time competing with top of the UFC featherweight division. Swanson came out victorious in that contest, but has since dropped two fights in a row. He was able to defeat Artem Lobov in April 2017, but was subsequently submitted via guillotine choke by BJJ ace Brian Ortega. That marked the third-straight loss via submission for the reputable stand-up fighter and his second-straight defeat via guillotine choke. Following his loss to Ortega – who is the next challenger for Max Holloway's featherweight strap -- Swanson was defeated via a convincing unanimous decision in a rematch with UFC stalwart Frankie Edgar. Swanson is undoubtedly one of the best featherweights in the world, but he seems to struggle when he fights uppe- echelon fighters in the division. His last victory over a top-ranked opponent was almost four years ago against now No. 4-ranked UFC featherweight Jeremy Stephens. At that time, Stephens was not at the top of the heap at 145 pounds.

At this point, it is hard to see where Swanson goes from here at 34 years old. With the exception of Stephens, who has greatly improved in the last four years, Swanson has been soundly defeated by the fighters ranked ahead of him. He could attempt to get back into contention in fights with those ranked immediately behind him in Ricardo Llamas, Chan Sung Jung, or Josh Emmett, but it is difficult to picture him competing with the fighters ranked ahead of him. Even though he is a BJJ black belt, it has been proven he cannot compete in the grappling realm with the likes of Edgar, Ortega and Holloway, and Stephens has shown great improvement in his striking that may pose problems for Swanson (who normally boasts excellent boxing).

Furthermore, in is rematch with Edgar, he was soundly out-struck, which has historically been Swanson's forte. At his age, it seems as if Swanson's better days are behind him and, should he be matched up with a fighter at the top of the division, he will likely be outclassed. His best bet would be to be matched up with a less experienced fighter such as No. 6-ranked UFC featherweight Josh Emmett. That would give Swanson a much-needed opportunity to to get a victory to get back into title contention.

Next Fight: TBA

Demian Maia, UFC, Welterweight

Maia is another aging fighter who has a difficult road ahead of him if he has hopes of contending for a title. Maia has dropped two fights in a row, and his dominant Brazilian Jiu-Jitsu has been nullified in those fights by superior wrestlers who do not allow the Brazilian to get the fight to the ground. His last two contests have been against current UFC welterweight champion Tyron Woodley and welterweight bad boy Colby Covington, both former NCAA Division I wrestlers. Both fights had zero takedowns recorded, which works against Maia's typical game plans. His striking is undoubtedly the worst aspect of his skillset, and it showed in those fights, as he was defeated convincingly in both fights via unanimous decision. If Maia cannot get the fight to the floor, he has very little to offer against top-of-the-food-chain welterweights in the UFC.

In his next fight, Maia squares off on short notice with No. 7-ranked UFC welterweight Kamaru Usman. Usman has been one of the most avoided fighters in the division. He has respectable stand-up skills, and captured an NCAA Division II national championship in 2010. Usman has never lost in the octagon and is riding a seven-fight unbeaten streak in the UFC. However, this is a huge step up in competition for the Nigerian-born fighter. Maia is the No. 5-ranked UFC welterweight and Usman has never faced a top 15 opponent in the UFC. Usman has respectable stand-up, but he prefers to take the fight to the floor. It will create an interesting dynamic if he shoots for takedowns, as Maia was only defeated by superior wrestlers when they chose to keep the fight standing and defended his takedowns. If Usman decides to go to for a takedown, it will give Maia, one of the best Brazilian Jiu-Jitsu practitioners in the history of the sport, an opportunity to submit Usman and vault himself back into title contention. At 40 years old this could be one of Maia's last chances to make a run at the title, and a loss to Usman could close the door on future title opportunities for the Brazilian welterweight.

Next Fight: Kamaru Usman, UFC Fight Night: Maia vs. Usman (May 19th, 2018)