NEW YORK - If a bird in the hand is truly worth two in the bush, then Mine That Bird is a very square bet at 2-1 to win the 141st Belmont Stakes: He's a known quantity with two strong efforts in the Triple Crown already to his credit, while his nine opponents are unproven colts of uncertain quality.\nFive weeks ago, Mine That Bird fell into that latter category. It was difficult to like him on paper in the Kentucky Derby without the assistance of several cocktails, and his runaway victory at 50-1 was a genuine shocker. But skeptical thoughts that it was a one-time aberration, a victory by default over a sloppy track that all 18 of his rivals disliked, should have been put to rest by his strong second to Rachel Alexandra in the Preakness. He not only came within a length of catching an extraordinary filly, but also beat the same colts who had tried him in Louisville two weeks earlier.\nI'm glad he's not going for a Triple Crown, because I would prefer that our next Triple Crown winner, especially after more than three decades without one, be a genuinely brilliant 3-year-old who deserves to be mentioned in the same breath as the immortals of the sport. Had Mine That Bird won the Preakness and was now the 3-5 favorite in the Belmont, I would be looking for someone to beat him. Instead, because some people still don't like or believe in him, you're getting an opportunity to triple your money on a Derby winner and Preakness runner-up in a field that's missing the two-three-four Derby finishers and the one-three Preakness finishers.\nYou would think from the morning line - Mine That Bird at 2-1, Charitable Man at 3-1, and Dunkirk at 4-1 - that these are three horses of very similar accomplishments. In fact, the second and third choices are works in progress surrounded by uncertainty. The biggest thing Charitable Man and Dunkirk have going for them is that they have raced only five and four times, respectively, and thus still have the potential to improve, but they will have to.\nCharitable Man is unbeaten on dirt and at Belmont Park, and comes off a victory there in the Peter Pan. That race fell into his lap, however, and he still has to prove himself racing beyond a one-turn, nine-furlong distance. That's as far as he has gone, and his two other victories were in sprints. Dunkirk made an electrifying middle move in the Florida Derby before settling for second, then flopped in the Kentucky Derby after a poor start. He has shown talent but has yet to win a stakes race. Both of these colts have enormous upside, but you also wouldn't be shocked to find out by fall that they're both better at a mile than at a classic distance.\nThe rest of the pickings are slim, though I hold out some hope for Summer Bird to get a piece of it at a price. He has made only four starts and has run by a lot of horses with a nice late kick each time. If you're going to guess on a horse's upside, better to guess at his at 12-1 than at 3-1 or 4-1 on the second and third choices.\nThe other six in the race are a pair from trainer D. Wayne Lukas, a pair from trainer Nick Zito, and a pair of Derby also-rans from California.\nLukas and Zito are Hall of Famers with multiple Belmont victories, and they have won the race with similarly iffy-looking horses (Commendable, Da' Tara). They have been at this long enough to know that if something goes amiss with the favorite, almost anything can happen. That, rather than any conviction they have a better horse than Mine That Bird, is why they're here.\nAs for the Californians, Chocolate Candy and Mr. Hot Stuff, at least you can say that neither has raced on a fast dirt track before, both having run only on synthetic tracks before floundering in the slop in the Derby. That technically makes them eligible to improve on conventional footing, the way I Want Revenge did this spring, but that colt is looking more and more like the exception in an otherwise subpar West Coast group that couldn't get near Mine That Bird in Louisville or Baltimore.\nSome view Mine That Bird as vulnerable simply because he ran in both the Derby and Preakness, since these days it's considered unusually demanding for any top horse to run three times in five weeks. Whether that's true or not, Mine That Bird has to qualify as one of the likeliest candidates to thrive amid such a challenge. He's relatively fresh, having raced only twice before the Derby this year, and his one-run style means that his races don't take that much out of him. He's training as if he's ready to run another big one.\nIf he does, the rest of this shaky field is in trouble, and 2-1 on the Derby winner could end up looking like a bargain.