We’re down to the Big Six and the Little 24. At this point in the NBA season, the wheat is long separated from the chaff. Twenty-four of the league’s 30 teams are no longer eyeing the championship as a goal, leaving only six with realistic hopes of hoisting the Larry O’Brien trophy in June.

While there’s a remote chance one of the other 24 could pull a miracle, all of them involve incredibly unlikely scenarios. For the Nets, for instance, the scenario would be Richard Jefferson coming back at full strength, Rodney Buford learning how to play basketball, Shaquille O’Neal getting diptheria, and Steve Nash’s car crashing into Tim Duncan’s. Not real likely, huh?

So let’s forget about those pretenders for the moment and focus on the Big Six. In reverse order, here’s how the title contenders shape up:

6. SEATTLE (49-22) The Sonics are an easy team to write off because they have so many weaknesses. They lack post scoring and a go-to superstar, they’ve had a spate of injuries, and Danny Fortson is reverting to his clubhouse-cancer past. What makes them hard to dismiss, however, is the fact that they keep winning. Even with a hobbled Rashard Lewis, Vladimir Radmanovic on the shelf, and Fortson a non-factor, the Sonics are 8-3 in their past 11 games.

But here’s another reason to like Seattle: They swept the season series with Miami and split with San Antonio and Phoenix. Seattle matches up very well with the top three contenders, particularly with the Heat. With an interchangeable five-man rotation at the power spots, Nate McMillan has myriad fouls to use against Shaq. Plus, considering Seattle’s dependence on 3-point shooting and lack of a post game, the Sonics aren’t too troubled by Shaq’s presence at the defensive end.

5. DALLAS (48-23) The Mavs are dangerous because they’re finally playing defense. Even before Avery Johnson took over, Dallas was defending much better than they had the past two seasons, and the Mavs have redoubled their efforts under the Little General. The key for Dallas is the health of center Erick Dampier, who is out with a stress fracture but should be back for the playoffs. If he’s in the lineup, the Mavs can hang with anyone; if Shawn Bradley and Alan Henderson are patrolling the middle, Dallas is in trouble.

Additionally, the little-noticed trade for Keith Van Horn is starting to pay huge dividends. Johnson periodically pairs the ex-Net and Knick in the frontcourt with Nowitzki, forcing the opponent’s big men to defend on the perimeter and leave the lane wide open for the guards. That’s the kind of match-up that could befuddle a Shaquille O’Neal or Tim Duncan.

4. DETROIT (44-27) The Pistons have to be included on this list for two reasons. First, as the defending champions, they should be considered a legitimate threat. But the bigger reason to like their chances is the Eastern Conference. Detroit and Miami are virtually guaranteed a spot in the Eastern finals by virtue of the mediocrity that surrounds them. So the Pistons only need to get hot for a few weeks in June in order to reclaim their championship. And as they showed a year ago, they can handle playing against Shaq.

I’d be more gung-ho on Detroit’s chances if the bench wasn’t such an eyesore. While it’s true that the second unit sees fewer minutes in the postseason, the bench also was a major catalyst in last year’s title run. Having it as a negative instead of a major positive robs Detroit of its mojo.

3. SAN ANTONIO (53-18) When everyone is healthy, the Spurs are the best team in basketball. The problem is that they’re not all healthy. Tim Duncan is out with a sprained ankle and could miss part of the first round of the playoffs, while Manu Ginobili is battling a sore groin. That wouldn’t be a problem if they were complementary players, but these two are All-Stars.

The injuries would be of less concern if the Spurs were in the East and could crush some hapless patsy in the first round while awaiting Duncan’s return, but that’s not the case. San Antonio’s likely first-round opponent is Denver, which has won 22 of its past 28 games. With Duncan available, the Spurs would easily hold off the Nuggets, but if he’s missing or limited by injury, it will be an uphill battle. Plus, even if San Antonio advances, it will have lost home-court advantage for a potential conference finals series against Phoenix.

2. PHOENIX (54-17) Everybody is rooting for the Suns because the brand of basketball they play is so exhilarating, and they just might pull it off. With Tim Duncan’s injury, Phoenix is in the driver’s seat to finish with the league’s best record and hold home-court advantage throughout the postseason.

With that, however, comes the top seed in the West, and that might not be to the Suns’ advantage. Phoenix’s likely second round opponent would be Dallas, a formidable opponent who might also benefit from its familiarity with Steve Nash’s tendencies and weaknesses. The Suns’ other weakness is the bench. Like Detroit, Phoenix rides its starting five and doesn’t get much help from the second unit, which leaves the Suns vulnerable should one of the top five get injured.

1. MIAMI (54-18) Of all the contenders, the Heat are in the best position. For starters, they play in the East. That guarantees them no major challenges in the postseason until the conference finals. Even in that round, likely opponent Detroit doesn’t seem nearly as imposing as a year ago. So Shaq and company should cruise into the Finals before they face a stern test.

More important is health. Yes, Udonis Haslem and Christian Laettner are out, but that hardly matters. As long as Shaq and Dwyane Wade stay upright, Miami has enough secondary players to bring it home. That’s a tremendous advantage. Detroit and Phoenix really need their entire starting five to stay healthy in order to win the crown, but Miami can lose almost anybody as long as its two lynchpins are functioning. Add it all up, and Shaq has a great shot at winning his fourth title in five years.