For the first time in a long time, Nets fans have reason to smile. The organization will move to Brooklyn for the start of the 2012-13 season, and stud point guard Deron Williams is coming along for the ride.

However, before Nets fans start celebrating uncontrollably, the trade general manager Billy King made immediately prior to re-signing D-Will should give Brooklyn cause for concern. On Monday, the Nets sent the expiring contracts of Jordan Farmar, Johan Petro, Anthony Morrow and Jordan Williams along with DeShawn Stevenson (via sign-and-trade) and a future first-round pick (lottery-protected in 2013 via Houston) to Atlanta in exchange for Joe Johnson.

Wait, the Nets got a perennial All-Star in his prime without losing any significant talent off their roster? Great move for Brooklyn, right? Wrong.

In today’s NBA, cap space and flexibility can oftentimes be more valuable then the accumulation of talented players. And in the trade for Johnson, the Nets squashed their ability to be players in the free agent market for years to come. In years past, the Nets have had an incredibly difficult time bringing in top-tier free agents. However, that was before they had one of the league’s elite point guards locked in to a long-term deal and before they moved the franchise to one of the most populous and popular cities on planet earth. One would have to assume that free agents throughout the NBA would be extremely interested in playing alongside Williams in Brooklyn, especially if the Nets could offer commensurate salary. Unfortunately, any cap space the Nets might have had is now tied up in a 31-year-old shooting guard.

Just how “cap-clogging” is Johnson’s contract, you ask? To help put the contract into context: Current restricted free agent shooting guard Eric Gordon just signed a “max” offer sheet with the Phoenix Suns for $58 million over four seasons. That is the highest amount he could have signed for. In contrast, over the next four seasons, Johnson will earn $89.4 million.

Johnson signed his max deal back in 2010, under the parameters of the old Collective Bargaining Agreement, which allowed him to ink a mind-boggling 6-year, $119 million pact. During the final year of his contract, he’ll earn a whopping $24.9 million. A legitimate argument could be made (considering length of the deal, total amount of money owed and age of the player) this is single worst contract in the NBA.

During the 2015-16 season, Johnson will be the highest paid player in the entire league. Yes, Joe will be paid significantly more than superstars such as LeBron James and Kevin Durant ($22.1 million and $21.2 million, respectively).

Assuming the salary cap falls somewhere in the neighborhood of $60 million (it currently sits at $58.2 million), Johnson alone will account for nearly 40 percent of the cap in 2015-16. Add in D-Will’s $20 million and the $10 million owed to Gerald Wallace, and the Nets will have nearly $55 million committed to just three players.

Johnson’s bloated contract was undeniably debilitating under the restraints of the old CBA, which is why so many pundits panned the signing immediately after it was first announced. However, a contract of that size becomes exponentially more constricting under the new CBA, which essentially enforces a “hard cap” apron of $74 million. Due to this reality, most everyone assumed the Hawks were stuck with Johnson for the duration of the contract. In fact, some suggested the best way for the Hawks to improve would be to amnesty Johnson and clear the remaining $90 million from the cap. It was assumed that if Atlanta attempted to trade Johnson, they would be forced to take back a nearly equally egregious contract that an opposing organization was looking to pawn off.

Amazingly, newly hired Atlanta GM Danny Ferry was able to not only trade Johnson for a gaggle of expiring contracts; he even got the Nets to include a first-round pick in the deal. The next day, Ferry shipped off Marvin Williams to the Utah Jazz in exchange for Devin Harris, who has just one year left on his deal. All of sudden, the Hawks are set to become major players in free agency as soon as next summer.

On the other hand, the Nets have sacrificed their cap space to bring in a shooting guard on the wrong side of 30. With roughly $50 million per season tied up in the trio of Williams, Wallace and Johnson, it will be difficult for Brooklyn to round out its roster and add significant frontcourt help. Now, if Billy King is somehow able to ply Dwight Howard from the Magic… well, that would be a complete game-changer. Howard, despite his sullied reputation, is undoubtedly a top-5 player in the NBA. A core of Superman and D-Will flanked by Johnson and Wallace would make the Nets arguably the second-best team in the Eastern Conference. However, Orlando shipping Howard to Brooklyn seems unlikely at this stage of the game.

Moreover, back to my original point, even if the Nets landed Howard, they’d still be better off without Johnson’s contract on the books. Think about how attractive a free agent destination Brooklyn would be if they boasted a tag-team of D-Will and D-Howard. Safe to say plenty of veteran free agents would be willing to take far less than market value to join tat group. But if the Nets were pinned up against a hard cap of $74 million, they wouldn’t be able to take advantage.

While Williams re-signing is the best news the Nets franchise has received in quite some time, one can’t help but think the day would be a bit sweeter in Brooklyn if King hadn’t foolishly traded for Johnson.