Yes, the Knicks stink. But that doesn’t mean we should go easy on the Nets.

The area’s lone professional basketball team – if by professional you mean, “rationally managed by people who appear to be grownups”- has nonetheless hit a few snags of late, and as a result seems in danger of failing to win the pitiful Atlantic Division.

New Jersey enters the weekend clinging to a half-game lead over the second-place 76ers, and are fortunate to be 23-21 on the season when one considers they’ve allowed more points than they’ve scored.

This is a huge disappointment, and only the staggering failure of the Knicks has prevented it from being a bigger story. If you told somebody at the beginning of the season that the Nets’ four best players – Jason Kidd, Richard Jefferson, Vince Carter, and Nenad Krstic – would be reasonably healthy through the first half of the season, then asked them to predict New Jersey’s record, they would have said something like 30-14.The Nets were supposed to contend for the Eastern Conference title, not to be hanging on the playoff fringe at midseason.

How does one explain such a disappointment? Two reasons stand out above all others: defense and the bench.

First, defense. I wrote earlier in the season that the Nets weren’t defending well, and in particular were giving up an obscene number of 3-pointers. They’ve only improved slightly in that department, allowing a league-worst 38.9% shooting from downtown.

But the other maddening failure is that the Nets are sending opponents to the line so much. One would think that if the Nets are forcing teams to beat them with jump shots, they at least wouldn’t be fouling, but in reality New Jersey allows .376 free throws per field-goal attempt – ranking them 27th among the league’s 30 teams.

That’s why the Nets rank in the middle of the pack defensively despite being good at everything else. They hold opponents to a low field-goal percentage, they force a decent number of turnovers, and they’re actually one of the best defensive rebounding teams in basketball (thanks to a point guard who rebounds like a center). That simple formula – force misses and get the rebound – has made the Nets one of the league’s best defensive teams throughout the Kidd era, but this year it hasn’t worked because there are too many open 3-pointers and too much fouling.

Both weaknesses point to the Nets’ problems in the paint. Because Krstic lacks strength and Jason Collins has been plagued by knee problems all season, New Jersey’s underbelly is much softer than it used to be. Inserting a well past-his-prime Clifford Robinson into the rotation hasn’t improved matters. Thanks to the weak frontcourt, the Nets have only two options: Double-team any good post player and concede open 3-pointers, or watch their big men get overpowered and resort to fouling.

Unfortunately, the frontcourt weakness also hurts the Nets at the offensive end. Despite the magnificence of Kidd, Jefferson, and Carter, New Jersey only ranks 17th in Offensive Efficiency (my measure of a team’s points scored per 100 possessions).Forgive me if this starts sounding just like last year, but the rest of the cast provides less support than a wet napkin. Collins’s knee injury has left him even more inert than usual, shooting a hideous 38.8% while averaging just 5.4 points per 40 minutes. In fact, according to my Player Efficiency Rating (which measure a player’s per-minute statistical production), Collins has been the NBA’s least effective regular player.

We can at least excuse Collins for trying to gut it out on a bad wheel – the Nets might be better off telling him to shut it down for a month. But what excuses can we make for the rest of the Nets’ supporting cast? Robinson and Jacque Vaughn are the two reserves who play the most, but both are shockingly bad offensive players whom defenses routinely leave wide open in order to double Carter or Jefferson. Forget averaging double figures by themselves – they don’t even do it combined.

Perhaps there’s a reason for optimism in all this, because further down the bench are a few Nets who might be able to provide some help. One can understand coach Lawrence Frank turning to Robinson and Vaughn in light of the team’s defensive woes at the start of the season, but if the Nets are going to be undermanned in the frontcourt anyway, they might want to try the opposite tactic and focus on winning shootouts.

That would put the Nets’ two most productive offensive reserves – Scott Padgett and Marc Jackson – back into play. Padgett has at least seen token minutes thus far, but perhaps he and Robinson should switch jobs. Yes, Padgett is roadkill against bigger power forwards, but he’s a much more accurate 3-point shooter, and he doesn’t share Robinson’s allergy to rebounding. As for Jackson, he’s been buried at the end of the bench for most of the season in spite of being the team’s most effective low post threat. He’s also the only big man besides the hobbled Collins with enough muscle to battle the Shaqs and Yaos of the world.

As for the backcourt, one wonders when Zoran Planinic will ever get a fair shot at a job. After playing well for Croatia in the European Championships this summer and having a decent preseason, the Nets extended his contract in the fall. Then they promptly hid him in the basement for six months. Planinic has seen only 227 minutes of action, and when he’s played he’s appeared to be on a very short leash with Frank. That’s unfortunate because Planinic’s high-risk, high-reward style doesn’t lend itself well to micromanaging.

It feels weird to second-guess Frank, since the Teaneck Terrier is probably the best coach the Nets have had since Larry Brown. But he’s not infallible, and the changes to the rotation he made at the start of the season may have been an overreaction to the early defensive struggles. Now, in the wake of the team’s continued mediocrity, it’s time for him to reevaluate those moves and see how he can energize the moribund second unit.

Of course, none of those moves can solve the Nets’ larger problems: They lack quality size, they lack bench players who can create their own shot, their best defensive player has a bad knee, and he’s probably doing more harm than good by trying to play on it. But in the forgiving Atlantic Division, a few tweaks to the rotation could be the difference between first place and the lottery. Frank is running out of time to choose the right ones.

Mr. Hollinger is the author of the 2005-06 Pro Basketball Forecast. He can be reached at jhollinger@nysun.com.