This article is part of our MMA Barometer series.

Plenty of well known fighters made headlines this week in the world of MMA. A legend of the sport, Tito Ortiz, retired on a high note with a first round submission win over Chael Sonnen in a fight that reportedly peaked with over two million viewers on Spike TV. The UFC made a change in the main event for the Halifax card on Feb. 19, scrapping the Junior dos Santos vs. Stefan Struve main event due to a Struve injury, and replacing it with another heavyweight bout between Travis Browne vs. Derrick Lewis. This was followed up by another major announcement, which finalized the headliners for UFC 209 in Las Vegas on March 4. The main event will be Stephen "Wonderboy" Thompson in a rematch against UFC welterweight king Tyron Woodley, who he fought to a draw in November. The co-main event of that card will be the fight many have been waiting for: a matchup between Khabib Nurmagomedov and Tony Ferguson to determine who gets the next crack at Conor McGregor's UFC lightweight title. The new Halifax main event will be a fun heavyweight showdown for the fans, and UFC 209 is shaping up to be a fantastic card.

As always, below is your MMA barometer with rising, falling, and check status fighters.

Rising

Ever since he lost to then-UFC lightweight champion Rafael Dos Anjos, Donald Cerrone has been on one of the best streaks of his career. After losing to RDA, Cerrone decided to move up to welterweight where the weight cut is not as hard on his body. It turned out to be an intelligent move for Cerrone, as he has won four fights in a row (all finishes), and garnered three Performance of the Night bonuses. The best part about his streak is that "Cowboy" has mixed up his game, and even though striking is his forte, he has included takedowns and grappling. This was evidenced in his submission of Alex Oliveira and in his win against Patrick Cote. The Cote fight was arguably his best performance at welterweight, as Cerrone outclassed the veteran Cote on the feet and was able to mix in well-timed takedowns. Even though Cerrone has been good at mixing up his techniques, his striking will always be his best attribute as evidenced by this four piece combination:

This Saturday, Cerrone will face a stiff test in MMA veteran Jorge Masvidal. Masvidal has competed over 40 times professionally, and much like Cerrone is a versatile fighter. He also used to fight at lightweight, so each fighter should be similar in size. It seems that Masvidal is the poor man's Cerrone. He is well-rounded, but in my opinion Cerrone is better wherever the fight goes, whether striking at a distance, in the clinch, or grappling on the ground. As a veteran it is very hard to finish Masvidal (he hasn't been finished in his UFC career), but the level that Cerrone is fighting at right now, and the fact that Cerrone will be performing in his home state of Colorado, makes it very possible that he will be the first UFC opponent to put Masvidal away.

Next Fight: Jorge Masvidal, UFC Fight Night: Schevchenko vs. Pena (Jan. 28, 2017)

Paul Daley (Bellator MMA - Welterweight)

Ever since his move from Strikeforce to Bellator MMA, Daley has looked great, winning 6 of 7 fights. The English kickboxer has finished four of those fights by way of KO/TKO, with three of those victories coming in the first round. Last Saturday Daley fought Brennan Ward and showed why he is one of the most feared strikers in Bellator. He landed a spinning elbow to stun Ward, and then followed that up with this vicious flying knee which knocked Ward out cold:

Daley has always been a great striker, even in his UFC days. However, his real test will come if he gets the fight he expressed interest in after his victory over Ward.

After his victory over Ward, Daley called out Bellator newcomer Rory MacDonald. MacDonald recently jumped from the UFC to Bellator, and he is a very difficult matchup for anybody at 170 pounds or 185 pounds in Bellator. One advantage Daley would have in a fight with MacDonald is the fact MacDonald has had to take a lot of time off from the sport to get surgery on his nose. MacDonald's nose was essentially shattered in a UFC welterweight title fight against Robbie Lawler, and he said it affected him in his loss to Stephen Thompson -- his final UFC fight.

MacDonald will not compete until Summer 2017, but if he fights Daley it would be an excellent matchup. If MacDonald's nose was still compromised, it could be difficult for him to handle Daley's power. But, if MacDonald comes back in the same form he was as the number one contender in the UFC, it could be a long night for Daley. Daley has traditionally struggled against elite fighters, as evidenced by losses to Josh Koshcheck, Nick Diaz, Tyron Woodley, and Douglas Lima. Daley has particularly struggled when taken down, which was how Koshcheck beat him in the UFC many years ago. MacDonald is such a well-rounded and intelligent fighter it is hard to imagine he would not try to grapple with Daley for the safest path to victory. Even though Daley has some grappling deficiencies, he still has the power to knock anybody out at welterweight. He would certainly have a fair chance against a Rory MacDonald coming off nose surgery and a long layoff. This fight is only rumored and has not been confirmed.

Next Fight: TBA

Check Status

After multiple injuries, Junior Dos Santos is ready to make his return to the Octagon. Dos Santos has alternated wins and losses since 2012, albeit against top-tier opponents. After a brutal knockout loss to Alistair Overeem in December 2015, "Cigano" bounced back with a brilliant performance in a unanimous-decision victory over Ben Rothwell in April 2016. His footwork and boxing were back on point, and the performance was night and day in comparison to his contest with Overeem. However, Dos Santos has not competed since that time due to shoulder surgery following the Rothwell fight. He was slated to fight Stefan Struve in Halifax, Nova Scotia, Canada on Feb. 19, but Struve was forced to pull out with an injury. Even though it delayed Dos Santos' return, it may have been a blessing in disguise, as he is now rumored to be the next opponent for UFC heavyweight champion Stipe Miocic at UFC 211 in May.

Dos Santos has lobbied for a title shot since Miocic defended the title against Alistair Overeem. This stems from his unanimous decision victory over Miocic in December 2014, which garnered Fight of the Night honors. It was a very close fight where each man took a lot of damage, and the rematch would likely be just as exciting. Miocic is a tough matchup for anybody with Division I wrestling credentials, as well as being a former Golden Gloves boxing champion. However, Dos Santos is a great foil for his style, as he possesses arguably the best boxing in the heavyweight division and 80 percent takedown defense over his UFC career. The big question will be whether, after major shoulder surgery, Dos Santos looks the same as he did against Rothwell a year ago. If he maintains his speed and his footwork is on point, as it was in the Rothwell fight, Dos Santos will give Miocic all he can handle. However, if he suffers from ring rust it could be a short night. Miocic has three first-round knockouts in his last three fights. This fight has not been confirmed, but it would certainly be an exciting sequel.

Next Fight: TBA

Falling

Ever since a first-round knockout of Brendan Schaub in December 2014, Travis Browne has won only one fight out of four. This coincides with his move from Team Jackson-Winkeljohn to Glendale Fight Club. Ever since the move, Browne has not been the same fighter. He is a massive heavyweight at 6-foot-7, 255 lbs., and couples that size with the athleticism of a former college basketball player. However, since his move, he has not shown the ability to use his size to his advantage, and his striking seems to have regressed. Presumably due to his limited success, Browne has once again moved camps to Black House in Los Angeles, California. He will train with his new camp for his UFC Fight Night main event matchup with Derrick Lewis.

Lewis is a difficult matchup for Browne, as he possesses some of the most devastating power in the heavyweight division. He has finished all his UFC victories via KO/TKO with the exception of his last performance against Roy Nelson. Browne is also primarily a stand-up fighter, but he holds a purple belt in Brazilian Jiu-Jitsu. Browne's best strategy would be to follow the same game plan Roy Nelson used against Lewis. Nelson lost a controversial split decision, but landed seven takedowns in that fight. Nelson is known as a brawler, not for his takedown ability. If Browne can do the same thing and stay away from getting into a brawl with Lewis, he has a good chance of being successful. However, Lewis was taken down four times in his last fight against Shamil Abdurakhimov and still found a way to survive and finish Abdurakhimov in the fourth round. Browne still has a chance in a stand-up war with Lewis, but his safest path to victory would be by grounding the dangerous "Black Beast." If Browne is not able to get back on the winning track, his time with the UFC may come to an end.

Next Fight: Derrick Lewis, UFC Fight Night: Lewis vs. Browne (Feb. 19, 2017)

B.J. Penn (UFC - Featherweight)

After B.J.'s last performance, it would be best if he retired from the sport. His 2014 fight against Frankie Edgar left a bad taste in his mouth because he was thoroughly beaten and ultimately finished, and he also had a bizarre strategy with an almost straight up-and-down striking stance. Penn wanted to come back and prove he could still compete in the sport, but it was shown he cannot compete with the younger generation of elite fighters. Yair Rodriguez dominated Penn before finishing him in the second round. The most discouraging aspect of the fight was Rodriguez reportedly had a sprained LCL, which almost caused him to withdraw from the fight. An in-his-prime B.J. Penn may have been able to compete with Rodriguez, but after a long career, the speed difference between the two fighters was shocking. Penn had no excuses, as he had an elite camp with the combined knowledge of Greg Jackson and striking guru Jason Parillo. Their combined knowledge was not enough to come up with a game plan to overcome the youth and speed of Rodriguez.

At this point, it would be best for Penn to call it a career. He is the most dominant lightweight in UFC history, and it does not make sense for him to cut to 145 pounds at his age. He has lost four fights in a row spanning back to 2011, and at two different weight classes. It is obvious he cannot compete with elite fighters anymore, and unless he chooses to compete against lower-tier fighters, it is in his health's best interest for him to retire. Jason Parillo recently said he thinks Penn will want to fight again, but this is a case where a proud fighter needs to be saved from himself by either his camp or the UFC. B.J. Penn is a legend of the sport and should not risk tarnishing that legacy by being a shell of his former self.

Next Fight: TBA