Many sports stars and athletes have tried their hands at mixed martial arts with varying degrees of success.

For every Brock Lesnar, there’s 15 other crossover athletes who did not have such a smooth transition into the world’s most violent and dangerous sport.

We here at LowKick MMA have compiled a solid list of 10 crossover sports stars who just couldn’t make it in mixed martial arts.

10. Jose Canseco

Jose Canseco had a long and storied career in baseball before trying his hand at mixed martial arts. The Cuban-American was a six time all-star and won two World Series championships with the Oakland Athletics in 1989 and New York Yankees in 2000 before a steroid scandal in 2005 tarnished his reputation as a professional athlete.

Four years after the steroid scandal, Canseco attempted a career in MMA. The former baseball star took on Korean giant Choi Hong-man at DREAM 9 back in 2009. It was the perfect freak-show fight for its’ Japanese audience, which was hosting DREAM’s Hulk Grand Prix.

Canseco, while a sturdy 6-foot-4 and 240 pounds, was dwarfed by Choi, who weighed in at 320 pounds while standing at a massive 7-foot-2. Canseco tried to stay light on his feet, at times running from Choi to reset at the center of the ring, but the big man eventually caught up to him, forcing Canseco to tap to strikes at just 1:17 minutes into the first round.

“That’s a big man,” Canseco said of Choi at the time. “I ran into one of his left jabs and that almost knocked me out. You have no idea how scary it was facing a man that big.”

Canseco would never fight in mixed martial arts ever again, and if his performance against Choi is any indication, he probably never will again. However, he did participate in a celebrity boxing match with former child star Danny Bonaduce in a match that went to a draw.

But, with 462 home runs to his name and 17 seasons in the MLB, Canseco will be remembered as a baseball player rather than a fighter.

9. CM Punk

The UFC had teased a CM Punk MMA debut for almost two years upon signing the former WWE superstar back in 2014.

Punk had unceremoniously left the leading pro-wrestling promotion and had hooked up with Duke Rufus’ gym in Milwaukee in preparation for a debut in mixed martial arts, but was fast-tracked once the UFC offered him a contract.

The WWE wrestler ultimately made his UFC and MMA debut against Mickey Gall at UFC 200, and the skill disparity was almost immediately on display.

Punk entered the bout at the already advanced age of 38 for a 0-0 mixed martial artist. Unsurprisingly, Gall toyed with the former pro-wrestler, who unlike fellow WWE to UFC defector Brock Lesnar, did not have the natural size or athleticism to carry him over into the world of real fighting.

Lesnar was a heavyweight who had to cut weight to make the 265-pound limit, and also had a collegiate and high school wrestling career to fall back on when it came to fighting in the UFC.

Conversely, Punk’s much smaller frame made him more suitable for the welterweight division, which has been one of the deepest and most dangerous weight classes in UFC history.

While Punk was indeed thrashed in his UFC and MMA debut, he vowed to continue training and fighting, but there has been no news of another fight since his loss to Gall.

8. James Toney

James Toney already had a stellar career in boxing before his lone MMA fight at UFC 118.

When the UFC announced they had signed the then-past his prime former boxing champ, it was a bit of a head-scratcher. He had zero ground game to fall back on and had seemingly gotten a bit out of shape since his championship days.

While many strikers like “Rampage” Jackson offered their services in welcoming Toney to the cage, the former boxer would end up drawing a much more difficult opponent for  his Octagon debut.

Toney took on former UFC light heavyweight and heavyweight champion Randy Couture in Boston, and the result was about as predictable as could be.

Couture wasted no time in taking down the boxer, completing the takedown with an ankle pick against a bewildered Toney. “The Natural” softened him up for a minute or two before mercifully submitting Toney with an arm-triangle choke just minutes into round one.

Toney would eventually return to boxing and never fought in MMA again. But with all this Mayweather vs McGregor talk lately, it’s interesting to see how far back this intersport rivalry goes.

7. Ray Mercer

The next crossover MMA fighter on our list is another former boxing great, Ray Mercer. Mercer had a short but storied career in mixed martial arts before retiring from combat sports altogether.

He took on Kimbo Slice back in 2007 in what amounted to an exhibition match. Kimbo actually opted not to strike with the boxer, and instead took Mercer down and submitted him.

But Ray Mercer preserved and ended up scoring one of the quickest knockouts in MMA history over a former UFC heavyweight champion.

Mercer took on Tim Sylvia two years after his loss to Kimbo, authoring an amazing nine second KO over Sylvia.

While that fight remains Mercer’s only MMA victory, the fact that it is over a former UFC champ and the quick nature of the knockout makes it an important and timeless highlight reel win.

6. Yuji Nagata

While a bit more of an obscure crossover, Nagata was a superstar pro-wrestler in Japan.

Nagata only fought twice in mixed martial arts, drawing the two most dangerous heavyweight fighters at that time in Fedor Emelianenko and Cro Cop.

He was knocked out both times, first by Cro Cop in 21 seconds back in 2001, and in 1:02 minutes by Fedor in 2003 under the infamous PRIDE banner.

Nagata spent a mere 1:23 minutes inside the mixed martial arts ring, and never competed professionally again.

Pro-wrestlers from all over the world seemed to have tried their hands at real fighting, but with the exception of Brock Lesnar and possibly Bobby Lashley, they were not met with much success.

5. Butterbean

Another boxer-turned mixed martial artist, Eric “Butterbean” Esch was known as the king of four rounders.

Out of all boxing-to-MMA crossovers, Butterbean had some success in transitioning from the sweet science, winning 17 MMA fights in his combat sports career.

Having competed for PRIDE in Japan and Cage Rage in the U.K., Butterbean spent considerable more time fighting in MMA than many of the other crossover athletes on this list. While the boxer did turn in seven KOs and ten submissions, his lack of a ground game was exploited quite a bit, losing nine times by submission, and many of those submissions via strikes after being unable to return to his feet following an opponents’ takedown and ground and pound.

Butterbean’s MMA career may not have been the worst overall, compiling a respectable 17-10 record in the sport before retiring in 2011.

4. Rolles Gracie Jr.

With a last name like Gracie, the expectations are sure to be fairly high when it comes to Jiu-Jitsu, but in MMA as well.

Royce Gracie won many of the UFC’s open-weight tournaments with his slick submission game paired with effective albeit basic striking.

While Rolles certainly excelled in his family’s own Brazilian Jiu-Jitsu, his time spent in MMA left a lot to desire.

Back in 2009, when the UFC announced Rolles Gracie, a HEAVYWEIGHT Gracie, was set to make his octagon debut against Joey Beltran, there was some hype behind him. He had modest 3-0 record in MMA prior to his UFC debut at UFC 109, but a Gracie with a heavyweight frame had some serious appeal amongst MMA fans at the time.

Unfortunately, Rolles took a pretty nasty and prolonged beating by Beltran. Gracie seemed in over his head from the moment the first bell rang.

His showing was so poor at UFC 109 that he was never given a fight with the promotion again. Gracie would pop up once more in MMA lore, when a knockout punch from Derrick Mehman sent him flopping to the floor like Rick Flair.

3. Muhammad Ali

Ali was perhaps the first ever boxer to transition into a proto-MMA type competition.

The year was 1976, and faked Japanese pro-wrestler Antonio Inoki issued a challenge to Muhammad Ali in a kind of mixed-rules exhibition match in Japan.

Ali had just come off a knockout over Richard Dunn. At the time, Ali had gone on recorded saying, “Isn’t there any Oriental fighter who will challenge me? I’ll give him one million dollars if he wins”.

Well he got the challenge he asked for. In their mixed-rules bout, which allowed essentially allowed for grappling and striking, Ali threw only six punches during the entire fight.

While Inoki basically laid on his back kicking Ali’s legs, he did end up giving the boxing boxing legend a nasty welt on his leg that drew blood.

The match was overall poorly received, but remains an important part of pre-MMA rumblings, the potential of which would be successfully exploited until decades later.

2. Roger Gracie

Putting another Gracie in this list is unfortunate, but both Rolles and Roger Gracie’s respective runs in the UFC/MMA are bad enough to warrant such attention.

Like Rolles and every other Gracie family member, Roger was already an accomplished Brazilian Jiu-Jitsu practitioner, winning numerous world BJJ championships, but like his fellow Gracies’, his striking was rudimentary at best.

Which is why Roger’s performance against King Mo Lawal in Strikeforce back in 2011. Gracie opted to stand and strike with the much more physically powerful Lawal, eschewing his world-class submission skills while hanging in the pocket with a dangerous striker (well, a dangerous overhand right).

The end result was predictable; Lawal scored a one-punch knockout in the very first round of their light heavyweight fight.

Although Roger Gracie would eventually compile an 8-2 MMA record overall, he couldn’t seem to win when it mattered the most.

After the UFC bought out and absorbed Strikeforce, where Gracie had received his first high-profile loss, he had one lone fight in the UFC, where he was soundly beat by Tim Kennedy at UFC 162.

The BJJ ace competed only two more times in MMA following his defeat to Kennedy and his unceremonious exit from the UFC.

1. Akebono

Perhaps the biggest (in every sense of the word) failed crossover into mixed martial, 6-foot-8 sumo wrestler Akenono fought four times in MMA, and lost all four of them.

When it came to sumo wrestling, Akebono was a stud. He made history in 1993 by becoming the first non-Japanese-born wrestler ever to reach yokozuna, the highest rank in sumo.

But all 550 pounds wasn’t enough to win a single MMA fight. He was submitted by the much smaller Royce Gracie in 2004, and followed that up with three more defeats, two of which were submission losses.

Akebono’s venture into MMA is proof that skill will trump size. If 170 pound Royce Gracie can tap a 550-pound man, perhaps the art of sumo wrestling isn’t suited for MMA.