It's a win-win situation

And here's the coda to the richest signing (for the moment) of an endorsement deal in the history of women in sports:

It's all about the incentives.

Which makes it, really, all about the motivation.

On the surface, of course, Serena Williams is supposed to be immune to this sort of carrot-on-a-stick manipulation. Williams' record certainly indicates so; the woman has won five of the last seven Grand Slam events in tennis and held the No. 1 ranking for more than a year before yielding it in August and going in for knee surgery. She's approaching a Tiger Woods-like performance plateau, only -- since it's tennis, and she's a woman -- without the global mania. Our unprecedented current ability to hype sports stars duly noted, it's actually possible that Serena will go underappreciated as an athlete in her time.

Still, when the ink finally dries on her new deal with Nike, perhaps its most interesting facets will fall somewhere between Page 20 and Page Infinity. They're the details that spell out just how motivated Williams is going to have to be.

It is an eight-year endorsement contract -- if. It's a $55 million agreement -- if.

If Williams meets certain performance criteria, that is. If, one suspects, she plays at least as much as she has been playing on the tennis tour, or perhaps more than she has been. If she maintains, let's say, a certain ranking, or collects a certain number of majors, or ... well, they base incentives on something, anyway.

And what's fascinating here is that Williams would agree to such a deal when, you figure, she doesn't necessarily have to. Puma would love to have her back. Reebok already has her sister Venus under contract; why not go for the family doubles team?

That's why this deal shapes up as so much more about Williams than about Nike. From where we sit, this is Serena essentially putting the pressure on herself to not only stay in tennis but also stay focused within it, at a time in her life when there are only about 200 other things competing for her attention and passion on a daily basis.

This is about Williams ensuring that she still pays attention to tennis. And while you might hear someone somewhere decry this latest gargantuan athlete endorsement, you'll get no squawk from us. If it keeps Serena on the court and going for the kill, it's a win-win.

The easy shot these days is the one from the top room of the ivory tower; it's the one that despises the modern athlete for having options and taking them, or for saying yes to ridiculous contract offers or taking guaranteed appearance fees or, say, plugging Buicks while driving Bentleys. It's the easy shot, and it misses the mark by maybe a dozen light-years of reality.

In reality, modern athletes have options their predecessors probably never even imagined, much less could have forecast. Succeed in sports, even for a couple of seasons, and you're on a fast track to a second, third or fourth career as a broadcaster, a fashion designer, a "consultant," a full-time pitchman. Lawrence Taylor had his career in the NFL, collected his most lurid and seamy outtakes, and got himself a second wind as an, ahem, author.

Look, it happens. You consider everything swirling around the heads of the elite or the anointed in a given sport -- think Woods, or the daily buzz that is LeBron James just now -- and it's almost remarkable that any of them sustain any truly memorable level of performance for long.

Almost from the first year or two they burst into the national sports consciousness, Serena and Venus Williams -- not particularly embraced at the start, smeared by association with their controversial father along the way -- have seemed at times ambivalent about their lives as athletes. Venus has spoken openly of a retirement from tennis at some point -- indeterminate, yes, but by her words clearly a point well before her potential in the game was exhausted. Serena, for a while, seemed the less motivated of the two players until she caught fire and assumed her rightful place (considering her skill and power) atop the game.

She is there now, undisputedly the best player in the game if healthy. She has a chance to do some work in tennis that would stand for decades or perhaps a generation. But on so many levels, it is about focus more than it is about knees that work and rotator cuffs that remain whole. It is about maintaining a visceral connection to the sport by constantly being a part of it.

If Serena Williams didn't want that connection, then she needn't sign a contract that places tennis incentives square in the middle of the deal. She wanted the deal anyway. If it is nothing more than Williams finding a new way to keep herself anchored to a sport at which she so excels, she's done herself the favor of the year. More power to her. Which is, of course, the idea.

Mark Kreidler is a columnist for the Sacramento Bee and a regular contributor to ESPN.com