For a minute, when his NFL career had come to an end, MMA enthusiasts were wondering the same thing: Why couldn’t Tim Tebow transition into MMA? He was doing some jiu-jitsu training with Ralek Gracie in Beverly Hills, and his buddy, former football player–turned–UFC fighter Brendan Schaub, stood out as a shining example that crossing over to the cage was possible. Tebow was a natural heavyweight, a tank with a holy corner, whose glaring lack of ability to talk smack could be the greatest thing to ever happen in MMA. And being such a polarizing figure with a built-in carnival spotlight, he could potentially earn millions (upon millions) of dollars while staying relevant.
Kind of like WWE’s Brock Lesnar, who shares the UFC record for heavyweight title defenses at two. Lesnar made a lot of cash just sort of trampling people in the octagon, people like "The Texas Crazy Horse" Heath Herring and a dramatically outsized 45-year-old Randy Couture. Lesnar was a former collegiate wrestler at the University of Minnesota, so he had some scaffolding in the mixed techniques. Tebow would have to acquire more than a rudimentary ground game, but he was a bruiser. If anybody could add the necessary pieces to kick ass in a cage, it was him.
Former WWE star CM Punk, who fights this Saturday night at UFC 203 in Cleveland, is different. Punk, whose real name Phil Brooks, just fetishized his way into a UFC fight. His MMA odyssey comes from an obsession to test himself in the literal realm of fighting against a nonscripted opponent who would like nothing more than to put him to sleep.
Nineteen months ago, in December 2014, the UFC announced the signing of CM Punk. The UFC was finishing a turbulent financial year and here was a celebrity from another sport coming into the niche realm. Anytime that happens, it’s titillating; the UFC loves associating with popular outsiders. And Punk, who comes for a different sector of the same entertainment world, is an interesting convert. Even at 37, after a long career in the squared circle, he has the semblance of a fighter.
Of course, for fans, there’s a morbid curiosity. Over the last year-and-a-half, while CM Punk has trained dutifully with Duke Roufus in Milwaukee, it’s felt like a countdown to his public failure — long, scenic walk to the gallows. In the eyes of many, his opponent, 24-year-old Mickey Gall (2–0), essentially won the CM Punk Lotto. He gets the chance to not only kick a famous interloper’s ass, but to make a name for himself in the process.
(Gall was discovered during his professional debut by UFC president Dana White on the pilot episode of his online reality series, Dana White: Lookin’ For a Fight, late last year. He won, and had the presence of mind to call out CM Punk, which struck everybody as a lovely idea. To help build Gall up, the UFC gave him a fight in February against 0–0 fighter Mike Jackson, who himself was a crossover from another world — Jackson was a part-time media member. In fact, after the fight, in which Gall choked him out 45 seconds in, Jackson grabbed his computer and sat down next to me on press row to cover the rest of the card. Technically, I am only twice removed from fighting Punk myself.
CM Punk isn’t the first to have a fascination with testing himself in a sanctioned mixed martial arts fight. There are many athletes and stars who see the cage as a dangling carrot to one day test themselves in, a calling that most will never answer. Here are a few that actually did.

Michael Westbrook, NFL Receiver
Even during his days as a wide receiver with the Washington Redskins and Cincinnati Bengals, Westbrook showed he had anything but soft hands. The most famous example came in 1997 when Westbrook punched the hell out of running back Stephen Davis during practice, a merciless beat down that served as a precursor for what was to come. Upon retiring in 2002, he began training in Brazilian jiu-jitsu, and and in 2008, won a tournament. In 2005, Westbrook signed on for a King of the Cage fight against fellow ex–NFL player Jarrod Bunch, winning via a first-round rear naked choke.
Yet in 2009, when Westbrook returned to King of the Cage after a four-year absence, he drew an up-and-coming Hawaiian heavyweight named Travis Browne (the same Travis Browne who fights this weekend in the UFC 203 co–main event against former champion Fabrício Werdum). Browne beat some sense into him. Westbrook tried one more time a few months later against journeyman Nick Gaston. Westbrook took a knee directly to the pills in the first minute and that was that, he couldn’t continue and never fought professionally again.
Grade: C
James Toney, Three-Weight Boxing World Champion
Maybe he got the idea after seeing former heavyweight champion Ray Mercer knock out the stiff totem figure of Tim Sylvia in an MMA bout a year earlier, but Toney was one of those guys chirping about boxing’s superiority over the hug-and-hump fest going on in MMA. UFC president Dana White rolled out an evil red carpet for him to come try it out. Toney fought 47-year-old Randy Couture at UFC 118 in Boston on merit of his boxing credentials alone. I visited Toney in the San Fernando Valley a month before the fight and watched his ovoid frame try to stuff takedown attempts for about 15 minutes, and remember thinking that the 5 percent chance most people were giving him was way too great.
Couture took Toney down 15 seconds in, and was in full mount at the 20-second mark. The crowd chanted "U-F-C" as Toney lolled on his shoulder blades like an upturned tortoise trying to right himself. He tapped out just after the three-minute mark.
Grade: D-
José Canseco, Six-Time All-Star MLB Outfielder
Only the author of a book called Juiced: Wild Times, Rampant ‘Roids, Smash Hits & How Baseball Got Big could find himself in Yokohama, Japan, fighting a 7-foot-2 Korean with such freak show aplomb. But that was José Canseco, the rogue Bash Brother who was never afraid to compromise such an abstract thing as "integrity." Canseco wore black sweatpants in his fight with Hong Man Choi, and he went chin hunting early, tucking his head into his chest and throwing overhand rights. But every time he got jousted by Choi’s preternatural jab, it turned into a slapstick affair, with Conseco running away like there was a swarm of bees after him. The end came at the 1:17 mark, with Choi raining punches down on Canseco’s curled-up body.
Grade: F
Shaquille O’Neal, 15-Time NBA All-Star
Technically, O’Neal never fought professionally, as there is no way he could get down to the 265 heavyweight maximum, but he flirted with the idea of fighting both Choi and Canseco. In fact, as recent as 2013 the two engaged in a pretty hilarious Twitter feud, which began with Canseco digging deep into his vocabulary, writing eloquently, "hey pussy @shaq." This would have been the best nonsensical fight since Screech fought Horshack on Celebrity Boxing, but it never materialized. It gets an honorable mention here, though, because the imagination is a powerful thing.
Grade: Incomplete
Herschel Walker, Heisman Trophy Winner and Two-Time NFL All Pro
The Strikeforce promotion, now defunct, wasn’t afraid to book cans against commodities like the former Heisman Trophy–winner Walker, who fought in January 2010 and 2011. In his cage debut, which came against Greg Nagy, he was 47 years old and still in amazing shape (he had eight or nine visible abs). Because he exercised obsessively after his football days, Walker had the cardio to go into the third round, which is when he put Nagy away with punches. A year later, he took out Scott Carson, who for all anybody knew could have been Salvatore Bellomo. This time he only needed three minutes to get the job done. Like Punk, Walker wanted to try out fighting as daredevil hobby, seeing how his fifth-degree black belt in tae kwon do would hold up in the cage. As former MMA writer Jake Rossen once said, "cagefighting is the new skydiving" for thrill seekers.
Grade: B+
Bobby Lashley, Former Two-Time NAIA National Wrestling Champion
Lashley, like Brock Lesnar, was a collegiate wrestler before he segued into the professional wrestling realm. He won national titles at Missouri Valley College and had his sights set on the 2004 Olympics. It’s almost unfair to include him, as he’s basically a multitasker who has fought 16 times in MMA (and won 14 of them), most notably against James Thompson (the guy that had his cauliflower ear popped by Kimbo Slice). In other words, he’s not fighting killers. Still, Lashley is built like a strongman from a Bugs Bunny cartoon, and each time he fights, it’s difficult to separate the wrestling caricature of him from the serious-minded MMA fighter.
Grade: B
The Green Power Ranger
When CM Punk signed with the UFC as a 0–0 fighter with no real merit, one of the first volunteers to greet him in the octagon was Jason David Frank, who played the green dude on the Mighty Morphin Power Rangers. By comparison, Frank had vast experience in MMA, having gone 1–0 as a pro and 4–0 as an amateur on the regional circuit in Texas and Virginia, all circa 2010. Punk and Frank went back and forth for a while, but ultimately the UFC (somewhat delicately) ignored Frank, and dredged up Gall from a regional theater show in Philly.
All things considered, the Green Power Ranger kicked a fair amount of ass. All four of his amateur fights — as well as his lone pro bout — ended in first-round finishes, the longest lasting just 2:09. What else would you expect from the most popular Power Ranger of all time?
Grade: C+
Matt Mitrione, Former NFL Defensive Tackle
It is true that Mitrione played in the NFL for the New York Giants and Minnesota Vikings before segueing into mixed martial arts, but "Meathead" strikes me more as a fighter who was barking up the wrong tree in football than the reverse. He’s been a steady fighter for his stints in the UFC and Bellator, and he doesn’t mind getting socked in the face. In 16 professional fights, just two of Mitrone’s fights went the distance. That streak of sadism could swing to football or fighting pretty seamlessly, but Mitrione looks right at home barefoot in the spotlight.
Grade: A-
Brock Lesnar, Two-Time NCAA All-American Wrestler, Former WWE Champion
Even though his big return fight at UFC 200 against Mark Hunt is now marred by the — ahem — shocking revelation of banned-substance use, the one-time NCAA national champion with the University of Minnesota turned WWE star is arguably the most successful person to crossover to MMA from another sport. The slow build? Hell no. In his second pro fight, he faced former UFC champion Frank Mir, a fight he lost. He later took the heavyweight title from Couture, redeemed himself against Mir, then scored a comeback for the ages against Shane Carwin at UFC 116. A digestive disease (diverticulitis) slowed him down for his fights with Cain Velasquez and Alistair Overeem, but by then he’d already silenced his critics.
If anything, Lesnar’s success has confused people as to what they can expect from CM Punk. Once again there’s intrigue about how a pro wrestler will handle himself in the reality-mongering world of cagefighting, yet there’s one major difference — Lesnar was a real wrestler before he ever set foot in the WWE, and Punk, well, wasn’t.
Grade for first UFC stint: A
Grade for second UFC stint: C (for clomiphene)
Johnnie Morton, Former NFL Receiver
The most ill-fated attempt at living out an MMA dream belongs to longtime Detroit Lions receiver Johnnie Morton, whose walk on the wild side ended up getting him carried out of the Los Angeles Memorial Coliseum on a stretcher. Morton, whom Jimmy Lennon Jr. announced as a "striker," came in jacked up for his heavyweight bout against the Ivory Coast’s Bernard Ackah. He wasted no time in flinging bombs at Ackah, who coolly returned fire and thwarted some early takedown attempts. Then, just a half-minute into the action, Ackah hit Morton with a right hand, and Morton dropped straight back like he was made of two-by-fours. If that weren’t bad enough, when his drug test came back from the commission, his testosterone to epitestosterone ratio was ever so slightly elevated. The state of California allows for a 6–1 testosterone to epitestosterone level. Morton’s came back 14 times over the limit, at 84–1.
Grade: F

For the most part, MMA has not been kind to visitors from other sports, though it is always excited to welcome cameo appearances. Part of the thrill of CM Punk trying his hand at MMA is that either he will fail (which is fully expected) or he won’t (because the sport thrives on lawless, apeshit happenings). CM Punk’s biggest problem is that he isn’t Brock Lesnar, or James Toney, or even Tim Tebow. All of them come from sports backgrounds. Punk comes from an entertainment background — albeit an athletic one — which makes you wonder if fighting out his dream in the UFC is a courageous pursuit, or a foolish one.
The answer is undoubtedly yes.
Chuck Mindenhall is a senior writer at MMA Fighting.