There are several MMA organizations, however. Furthermore, the UFC is like the NFL of MMA. In general, the best fighters fight for the UFC because it is the most popular and has, therefore, the most economic potential.
WAMMA probably has Fedor on some contract/money lockdown preventing him from fighting in the UFC. I highly doubt he would beat the current UFC champion Brock Lesnar, who is a f*cking monster.
Fedor is by far the best heavyweight fighter in the world, and is arguably the most complete pound for pound mixed martial artist currently competing. He has dominant wins over almost every major heavyweight fighter, including past champions in Pride and UFC. e.g. Nogeira (twice), Crocrop in his prime, Tim Sylvia, Arlovski, and now Brett Rodgers. He's beaten plenty of other famous and talented fighters like Matt Lindland, Babalu, Coleman/Randleman, Mark Hunt, Herring, Arona etc. etc. etc. The only major heavyweights he hasn't fought are Josh Barnett, Frank Mir, and Lesnar, of which Mir and Lesnar only recently became significant. The only reason he hasn't fought Barnett is because Josh failed the steroids test (and helped put the nail in Affliction's coffin).
His only loss was a cut from an illegal elbow (9 or 10 years ago), and he's only been in trouble once or twice in his career, the last of which was against Fujita 6-7 years ago, where after getting rattled, he immediately submitted Fujita.
Can he lose? Yes. In MMA, everyone is fallible and capable of losing. Even Kimbo could toss a lottery-winning haymaker and knock him out, but it is very very very very very very unlikely. Would he beat Lesnar? Probably 9 times out of 10. He's fought much bigger opponents without difficulty.
Still, we'll most likely never see him in the UFC because he is loyal to his Russian managers/promotors, who are adamant that their name brand (
M-1) be a co-promotor with any Fedor-involved UFC fight, to which the UFC has said absolutely no. Dana White has tried very hard to get Fedor, and it's most likely never going to happen. This is the main reason that Randy Couture left the UFC a couple years ago, as he wanted badly to fight Fedor, and didn't think the UFC could make it happen.
Lesnar vs Fedor would be a SICK fight but I'd have to give the advantage to Lesnar. He's a complete MONSTER. And he's only getting better with every fight.
A monster fighter who's "getting better all the time" may beat someone like Frank Mir who is talented and likeable, but has big gaping holes in his game. However, beating a Sambo master who is literally the most complete mixed martial artist of all time, who has shown himself to have a very solid chin, scarily accurate striking, and very good submission game from the bottom, is very very very very unlikely, as I said before.
It would be interesting to see Fedor and Andersen Silva at a catch weight of 220 or so. Silva is said to 'walk around' at 220, and Fedor goes about 230...pretty close. Nobody has even come close to beating Silva in recent years. The guy is pretty amazing.
This would definitely be an interesting fight. However, Fedor has done this before, having fought the previously top ranked middleweight Matt Lindland, and he made very short work of him.
Also, it's untrue that nobody has come close to beating Silva. Even an emaciated Travis Lutter had him in trouble. Both Dan Henderson and Nate Marquard have legitimate chances of beating him. Still, put him up against overrated cans like Forrest Griffin, and he'll look unstoppable every time.
Fedor was amazing in Pride but in this fight he looked old and in need of some gear.
Does Strikeforce drug test?
Yes, Strikeforce drug tests. MMA in the states still has to be governed by the regional state athletic commisions. I think the last fight was in Illinois (Notice it was the Strikeforce/
M-1 fight).
I don't think there's any doubt that 1) Fedor is the best heavyweight fighter in the world, and 2) Fedor is past his prime. I also believe that the best heavyweight athletes in the world are not fighting MMA, but instead playing football in the NFL. There are NFL athletes that walk around at 270lbs that are quick and agile, and would make Lesnar look stupid (like they did when he tried out for the Vikings). Still, since there wasn't money in MMA until recently, there isn't a big pool of NFL-level talent doing MMA. Now that MMA is huge, and people will be 12-15 years old learning jujitsu, we can expect that 10 years from now there will be a large stable of fighters that could give Fedor a run for his money. Then again, hopefully by then Fedor will be retired, unlike Couture......