Whenever we see two former champions square off in a bout with intentionally unclear future implications, it's hard not to wonder if we're about to witness a swan song or a comeback tour.
Of course, when Quinton "Rampage" Jackson (30-8) and Lyoto Machida (16-1) meet at UFC 123 in Detroit on Saturday night, it's not so far-fetched to think it could be a little of both.
It's not about age or deteriorating ability for these two. Both are still in their early 30s, still close enough to their respective primes that another run at the UFC light heavyweight title is perfectly feasible. Instead, this is more a question of desire. Machida has given us no reason to doubt that he has it, while Jackson's motivations for getting in the cage seem to change with the seasons.
One day "Rampage" will tell you he's only fighting for the paycheck, and that he's perfectly willing to hang up the gloves if his acting career takes off. One decision loss later and it's all about honor for him, just like it was back when he was a star of Japan's Pride Fighting organization.
Jackson has never been a fighter who deals with losses all that well. He's been known to blame anything from pernicious poisoning to ill-advised fasting to secret personal problems when a fight doesn't go his way, and his motivation tends to wax and wane depending on how bright his prospects are at any given moment.
You put that all together and what you have is a fighter who is mercurial at best. His physique always looks as if it's ready to go on fight night, but it's often hard to tell if his mind is in there with it.
The mental game will be especially important on Saturday, as Jackson faces one of the most frustrating fighters in the 205-pound division. Depending on what you think of him, Machida is either brilliantly elusive or painfully boring. But even his detractors have to admit that he excels at moving in and out of his opponent's range, staying just long enough to land a quick salvo and then disappearing before he can be hit with a counter-attack.
If Jackson isn't psychologically ready or able to deal with that, fifteen minutes in the cage with Machida could be a very long time. Jackson not only needs this win to stay relevant in an increasingly crowded division, he also may need it just to convince himself that the paychecks are still worth the pain.
By now, Matt Hughes and B.J. Penn know each other better than some married couples. They've had two memorable UFC title bouts with each man claiming a definitive win for his highlight reel, so why not have a rubber match while the UFC tries to figure out what do with them next? Hughes liked the idea so much that he cleared his calendar during hunting season to prepare for it, which is saying something. There may be only one thing Hughes loves more than firearms and the outdoors, and it's earning bragging rights over an old rival.
But this fight finds the two men at different stages in their careers. The 37-year-old Hughes is on a three-fight win streak, but could easily stroll off into the sunset as an MMA legend any time he chooses. His chances of ever becoming welterweight champ again are miniscule, at least as long as Georges St. Pierre is healthy, but he seems content to play the elder-statesman role for now, and the UFC is just as content to arrange those types of fights for him.
Penn, on the other hand, is a bit more directionless. Having just lost two straight lightweight title fights, he needs a high-profile win to show that he's still capable of the kind of dominance that ruled the 155-pound class for the last two years. You could argue that beating an aging welterweight doesn't necessarily prove that, but the history alone is enough to make this one interesting.
With Penn, the question is always conditioning. At welterweight he doesn't need to work as hard to get in shape, and in the past he's sometimes opted not to. A three-round fight is slightly less grueling, but he'll still need to be sound of body and spirit to beat Hughes, who knows what he's good at and doesn't depart from it.
Expect Penn to have a serious speed advantage on the feet, but it's takedowns that may decide the fight. Penn must be able to shut them down as well in the second and third rounds as he historically has in the first if he wants to get his hand raised.
The undercard of UFC 123 features three up-and-comers from three different divisions, all in various stages of the crucible that comes before true stardom.
The closest to the top of his class is lightweight George Sotiropoulos, who's won six-straight in the UFC and could easily be up for a title shot soon if he can beat Joe Lauzon. As long as Sotiropoulos can get the fight to the mat on his terms, he should be able to edge this one out.
Next there's light heavyweight and former NCAA wrestling champ Phil Davis. Even if he hadn't picked up many new skills since his days at Penn State you'd still have to like his chances against Tim Boetsch. Factor in Davis' improved striking and not insignificant submissions game, and this starts to feel like a mismatch.
Finally, you've got Ultimate Fighter alum Gerald Harris, known to Sportscenter viewers simply as "that dude who slammed that other dude." While his knockout of David Branch will live on in highlights for future generations to enjoy, he's got to show that he's not just another occasionally interesting middle-of-the-pack middleweight. Brazilian Maiquel Falcao -- a newcomer to the UFC with plenty of experience back home -- will likely get right in his face and practically demand that he sink or swim on live TV. You can't ask for a much better chance to shine than that.