On Saturday night in Dallas, age finally caught up to the Mavericks. Without Tyson Chandler protecting the lane, there was no one to clean up the dribble penetration the Dallas veteran guards allowed. As a result, the Oklahoma City Thunder ran a train at the front of the rim, outscoring Dallas 35-16 in the fourth quarter of Game 4.

Now, with only six players under contract headed into the summer of 2012, Dallas may have a drastically different roster surrounding Dirk Nowitzki next fall. The Mavericks' lack of sentimentality as an organization has allowed them to remain relevant for well over a decade, as 2012 will be the third time the franchise has rebuilt the roster around Nowitzki.

When he first came into the league, Nowitzki was a part of a “Big Three” with Michael Finley and Steve Nash. A young offensively-minded team without an interior defensive presence, they were in the shadow of Chris Webber’s Sacramento Kings for the early part of the decade, with their only trip to the Conference Finals coming after Webber tore his knee against them in the 2003 playoffs.

Nash’s departure to Phoenix coincided with Avery Johnson taking over from Don Nelson, as Dallas began trying to build a team that could match up with Tim Duncan’s San Antonio Spurs. They brought in two massive seven-footers (Erick Dampier and DeSagana Diop) to battle Duncan in the low block, as well as a speedy young point guard (Devin Harris) to combat Tony Parker.

That team peaked in 2006, when they defeated San Antonio in a classic second-round series decided by Nowitzki’s and-1 with less than 10 seconds in Game 7. However, their small backcourt of Jason Terry and Devin Harris couldn’t keep bigger guards like Dwyane Wade and Baron Davis in front of them, while Dampier and Diop didn’t have the foot-speed to cut off penetration in the lane. After coming up short for more than half-a-decade, Nowitzki and the Mavericks were written off by most of the NBA.

However, they continued to revamp their roster, adding a two-way point guard (Jason Kidd) and an elite perimeter defender (Shawn Marion) to put around Nowitzki and Jason Terry. But it wasn’t until they added Chandler, an elite defensive seven-footer, that the Mavericks were finally ready to take the final step.

The Nowitzki/Kidd/Chandler Mavericks were able to win where the Nowitzki/Nash/Finley and Nowitzki/Harris/Josh Howard units didn’t because they were built to maximize Nowitzki’s strengths and minimize his weaknesses. They had long and versatile frontcourt players who could cover for him defensively as well as shooters who could punish teams for double-teaming him.

But instead of going all-in on one final run in 2012, the Mavericks let Chandler walk in free agency, becoming the first championship team since the 2007 Miami Heat to essentially pass on defending a title. Besides Nowitzki, the only players under contract for 2013 are Marion, Brendan Haywood, Rodrigue Beaubois, Brandan Wright and Dominique Jones. Haywood, who is set to make $27 million dollars until 2015, will almost certainly be amnestied.

They have a blank slate to build around Nowitzki, but for the first time since he’s been in Dallas, it’s no longer clear he’s worth being built around. He had his worst statistical season since 2000, shooting 45.7% from the floor and grabbing only 7.4 rebounds a game. While a lot of that has to do with a bizarre lockout-compressed season that was brutal on the legs of the NBA’s veterans, championship teams aren’t generally built around players entering their 15th season in the NBA.

Nowitzki’s two contemporaries at the power forward position, Tim Duncan and Kevin Garnett, have long since ceded control of the offense to an All-Star point guard. That, of course, is where Deron Williams comes in, as the New Jersey Nets' point guard is the main prize available in free agency.

Williams, an athletic 6’3 210 five-tool point guard, is a legitimate All-NBA player. However, for all the publicity the position has received in the post hand-check NBA, a great point guard does not guarantee title contention. Chris Paul’s New Orleans Hornets teams only won one playoff series, while Williams and Steve Nash have both missed the playoffs the last two seasons on teams that lacked a great big man.

For Dallas, the Williams/Nowitzki duo would be a modern-age Stockton/Malone, but it wouldn’t be enough. They would still need to upgrade their interior defense, especially with Haywood gone and Ian Mahinmi in line to receive a substantial contract due to the lack of centers in the modern NBA. Wright could be an excellent third big man on an elite team, but he doesn’t have the bulk to play the center position full-time, especially in a conference with Andrew Bynum and Marc Gasol.

That’s why letting Tyson Chandler walk was such a gamble for Dallas, as there’s no guarantee they can find another center capable of anchoring a championship-caliber defense. Despite having one of the most active front-offices in the NBA, it took the Mavericks 12 seasons to find Chandler. Without him, their last remodeling around Nowitzki wouldn’t have worked, and without another great defensive center, their next won’t work either.

Dallas essentially put all their chips in on Dwight Howard, a player with a herniated disk who has become famous for his indecisiveness. However, when healthy, he has the talent to swing the balance of power in the NBA. And in a league where super-teams are becoming the norm, a trio of Williams, Howard and Nowitzki would match up extremely well with the Miami Heat and the Thunder.

It’s all or nothing for the Mavericks this summer, which is why Dallas will be the most intriguing team in the NBA as we head into the first full-fledged off-season since “The Decision”.