UFC 147 features two aging legends in the main event, with Rich Franklin and Wanderlei Silva expected to go toe-to-toe in what may shape up to be a retirement bout for whoever loses.
37-year-old MMA legend Tito Ortiz also plans to retire following his upcoming bout with Forrest Griffin.
With so many UFC fighters creeping up in age and nearing retirement, the focus turns to the next generation to keep the league moving in a positive direction.
Here's a look at the top ten UFC fighters 25 years old or younger:
1) Jon Jones: The 24-year-old Jones is the youngest UFC title holder in history, and all signs point to a long reign of dominance by him in the UFC Light Heavyweight Division. He's on a seven-fight win streak dating back to 2010.
2) Rory MacDonald: The 22-year-old Canadian has the look and feel of a young Georges St-Pierre. Perhaps that shouldn't be all that surprising, as he trains with St-Pierre at TriStar Gym in Montreal. He's a winner of three straight, and his upcoming bout against B.J. Penn is his first true test against a legend.
3) Demetrious Johnson: "Mighty Mouse" might just be the fastest MMA fighter in the world right now, and he's slated to get the first crack at the UFC Flyweight title with an upcoming bout against Joseph Benavidez.
4) Jose Aldo: Aldo hasn't lost in over six years, and his leg kicks are perhaps the most devastating in the league. He has defended his UFC Featherweight Championship Belt three times, but he's been watching from the sidelines lately while nursing injuries.
5) Renan Barao: This 25-year-old Brazilian is riding a 28-fight unbeaten streak, believed to be the longest current stretch of wins in MMA.
6) Stefan Struve: By the time his UFC career is done, Struve may have the league's most victories among heavyweights. At just 24 years old, he already has eight wins in the octagon.
7) Michael McDonald: McDonald, just 21 years old, hasn't lost in over three years and is riding an eight-fight win streak. He recently knocked out the legendary Miguel Torres for his fourth straight UFC victory.
8) Chan-Sung Jung: "The Korean Zombie" is one of the most exciting fighters in the UFC's Featherweight Division. The 25-year-old is 2-0 in his UFC career, including epic wins over Mark Hominick and Dustin Poirier.
9) Dustin Poirier: The 23-year-old Poirier is a perennial contender in the UFC's featherweight division. Besides his recent loss to Jung, Poirier looked beastly in his pro career, with convincing wins over Max Holloway and Pablo Garza.
10) Alexander Gustafsson: This 25-year-old Swedish brawler is quickly climbing the ranks of the light heavyweight division, as he recently notched victories over elite competitors like Matt Hamill and Thiago Silva. A couple more wins and we may see Gustafsson stepping in with Jon Jones, which would be an absolute treat for fight fans.
Eric Holden is a lifelong UFC fan. Follow him on Twitter @ericholden.
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