Most Unrecognisable Fighters Since Their UFC Debut

A successful MMA career could last an extremely long time. Take Jim Miller, for example, who made his UFC debut in 2008. Or look at the career of Clay Guida, a man who debuted back in 2006. We watch them grow in the sport, both in a professional sense and physically.

Raul Rosas Jr gained a UFC contract at 17, meaning he could have upwards of 20 years in the sport. To look at him on his debut in comparison to 20 years time will show a stark difference.

We take a look at UFC fighters who look considerably different now, in comparison to when they made their UFC debut.

Most Unrecognisable Fighters Since Their UFC Debut

Conor McGregor

Making his UFC debut all the way back in 2013, Conor McGregor has grown in the sport since first making the walk. Taking on Marcus Brimage, The Notorious was not nearly as physically big, far less tattooed and sported a boy-ish look.

Fast forward to 2025 and although we haven’t seen McGregor in the octagon in a number of years, his return is seemingly imminent. He looks vastly different today too, almost unrecognisable to the man who first walked to the octagon in Sweden some 12 years ago. He’s much, much bigger physically. He’s grown into a full sized welterweight in recent years. He’s covered in tattoos, most famously his gorilla wearing a crown with a heart in its mouth on his chest.

It would be fair to say that from his UFC debut to today, he’s a whole different person… being the biggest star in history will do that to you.

Jared Cannonier

If you’d have said that a former heavyweight would make his way down to light heavyweight and then cut a further 20lbs to middleweight to become a title contender, few would have believed you. That’s just what Jared Cannonier did!

Debuting in 2015 at heavyweight, Cannonier went 1-1 at the weight before deciding that he was to change things up and move down to 205lbs. Going 1-3 at light heavyweight saw him needing to make further changes. (It’s worth noting that he did only lose to two future champions, Glover Texeira and Jan Blachowicz and a future title contender, Dominick Reyes).

Then came the ambitious move down to middleweight. Taking into account that he debuted at 235lbs, Cannonier stepped on the scale to face David Branch at 184.8lbs, under the middleweight limit! The transformation is truly incredible and Cannonier was extremely competitive at middleweight, realising a title shot in 2022.

Heavyweight ➡️ Light-heavyweight ➡️ Middleweight

Jared Cannonier with an insane body transformation 👏#UFCCopenhagen pic.twitter.com/R5ew0juy5P

— UFC on TNT Sports (@ufcontnt) September 27, 2019

Sean Strickland

In 2015, Sean Strickland stepped into the UFC octagon sporting long locks of hair, looking chiselled at 170lbs, looking to maintain his undefeated run and progress to 16-0. It wasn’t to be, however, as he would lose on the night.

Was it the hair that let him down? He would sport a shaven head next time we saw him fight, this time winning via decision.

Fast forward to the modern day and Strickland is now a former middleweight champion but will go down as one of the most underwhelming fighters in UFC history. In his 16 UFC wins, the American has only finished five fights, one of which came in his debut. Did losing the hair lead to him losing some of his aura? It’s unlikely, but a good fan theory nonetheless.

Jake Collier

Jake Collier is much like Jared Cannonier but in reverse. He began his UFC career at middleweight in 2014 and after four fights at the weight, moved up to light heavyweight.

After just two fights, Collier was banned for PED use and took some time away from the octagon, returning almost unrecognisable.

He returned at heavyweight and, unfortunately for him, ran into a debuting Tom Aspinall. He would go 2-6 at heavyweight before being cut. From his UFC debut to being cut in 2023, Collier is almost unrecognisable.

Rose Namajunas

Making her UFC debut at just 22 years old, Rose Namajunas appeared to be the future of the sport for years to come. She competed for the inaugural UFC strawweight title against Carla Esparza, who was also making her UFC debut. She was young, inexperienced and most strikingly, had a long head of hair. Although she would lose on this occasion, she would hit form and progress to 4-1 in her next five fights.

She would recognise gold, upsetting long-time champion Joanna Jedrzejczyk, cementing herself as a strawweight to be respected. Although she would have an up and down strawweight career, a lacklustre performance in a title fight loss to Esparza in their rematch saw a shift in weight to flyweight. Thusfar, Thug Rose has gone 3-2 at 125lbs, packing on size, entering each fight with a whole lot more experience and now sporting her shaven head.

What the future holds for the now 33 year old isn’t known, but what we do know is that she has changed a lot since her UFC debut!