Welcome to ESPN Insider's first annual look at the top 25 MMA fighters under the age of 25.
In traditional team sports, talent is cultivated from an early age and skills are refined through years of experience. However, unlike their counterparts in team sports, mixed martial artists typically first specialize in a single discipline, (e.g. jiu-jitsu, wrestling, judo) then expand on their talents after successful amateur or professional careers. Expertise takes time and to become proficient in other disciplines means that these athletes often go well past their 25th birthday to become true mixed martial artists.
However, as this list illustrates, there is an increasing number of fighters who've enjoyed multi-disciplinary training early on as amateurs and find themselves out in front of their counterparts in terms of performance, experience and marketability. Rory MacDonald, who tops our list, was reared in a multi-disciplinary environment and exemplifies this new trend within MMA.
Fighters were broken down into two categories: "Current" and "Future." Current is an accumulation of relevant statistics, notable achievements and anecdotal moments that justify their inclusion on the list. Future outlines the fighter's strengths and weaknesses, possible career arc and an assessment of their marketability. A fighter must be 24 years old on or after Feb. 4, 2013 to be eligible for the list. Decisions were weighted between an assessment of the fighter's past performances and his projections as a future star of MMA.
The reality of MMA is that it takes more than great skills to succeed in the cage. A future star has to be the perfect mixture of talent, hard work and an engaging self-promoter, with the chance to prove their mettle on MMA's biggest stage.
So let's get on with MMA's top 25 under the age of 25:
Current: The most successful fighter on the list, Rory MacDonald is on a four-fight win streak with victories over former UFC champion B.J. Penn and Nate Diaz. Carlos Condit's come-from-behind win against MacDonald at UFC 115 is his only blemish. In six UFC fights he has never lost a round on the scorecards, and the two fights that went to decision were scored 30-26 on two judges' scorecards. In his six UFC fights, MacDonald has landed 266 significant strikes and owns a takedown differential of plus-15.
Future: If you believe in numbers, then MacDonald is only getting better with age. As seen in his recent destruction of Penn, the Canadian's size, speed, strength and fighting attitude all indicate a championship career. Should he avoid a welterweight matchup with friend and training partner Georges St-Pierre -- and get past a rematch with Condit on March 16 at UFC 158 -- MacDonald should see a title fight within 18 months.
Current: One of the youngest fighters on the list, McDonald has used back-to-back knockouts of Alex Soto and former WEC champion Miguel Torres to propel himself into the title fight for the UFC bantamweight interim belt against Renan Barao on Feb. 16 at UFC at Fuel TV 7. McDonald's heavy hands and 70-inch reach could create problems for Barao if the California fighter can woo the hard-pressing Brazilian into fighting from a distance. His aggressive style has already won him a loyal following as well as bonuses for "Knockout of the Night and "Fight of the Night."
Future: For "Mayday" the future is now. Only 22 years old, McDonald is an established fighter in a promotion that gives significant financial incentives to those who are able to stay active in the Octagon. Technically, McDonald should have the hand speed to keep up with Barao, though it'll be important for him to use his length and create distance for his striking. Should McDonald win, he has shown that he's also nimble enough to contend with UFC champion Dominick Cruz.
Current: The "Skyscraper" is best known for his UFC-leading height, but in 12 UFC fights dating back to 2009 the Dutchman has posted a 9-3 record, submitting four and knocking out four opponents in the Octagon. Long-legged and opportunistic, Struve average 3.92 submission attempts per 15 minutes in the Octagon, good enough for fourth all-time in the UFC. The Dutchman is on a four-fight win streak, earning two "Submission of the Night" awards, and his last fight against Stipe Miocic won "Fight of the Night." He's midcareer at 24, but in the heavyweight division your chin matters and Struve has been KO'd three times in the UFC by Travis Browne, Roy Nelson and Junior dos Santos.
Future: The addition of Strikeforce fighters Daniel Cormier, Bigfoot Silva and Alistair Overeem will make it tougher for Struve to find a title shot in 2013. However, if Struve can avoid being knocked out and possibly secure submission or knockout victories of his own, the UFC will give him marquee fights and the path to a title fight. For now he's scheduled to face heavyweight Mark Hunt on March 6 at the UFC on Fuel TV 8 in Saitama, Japan.