There will come a day when Dirk Nowitzki can no longer hoist an NBA offense on his shoulders and singlehandedly drag it across a finish line. One of the sturdiest tentpoles in basketball history will splinter, and the Dallas Mavericks will need to orbit a much younger sun.

Heading into this year, that day was thought to be right around the corner. Instead, it miraculously still sits beyond the horizon. Only the San Antonio Spurs, Golden State Warriors, Atlanta Hawks and Cleveland Cavaliers have more wins than the 7-4 Mavericks, a squad that's nowhere near full strength.

At the center of it all is a 37-year-old seven-footer who's more constant than a glacier. Nowitzki is currently aiming to create the 50/50/90 club. His True Shooting percentage is the best it has ever been, and he basically never turns the ball over. For that, his PER and Win Shares per 48 minutes are both well above his career average. A handful of guys surpass Dirk's ability to discombobulate defensive schemes without ever touching the ball (by a handful I mean only Stephen Curry), and when it finds his hands, few are more efficient spotting up, popping out after setting a screen or going to work in the post.

The guy's gravity is ridiculous. His shadow looms as long and wide as it ever has, and his positive influence on teammates is immeasurable. For years, Nowitzki's screens opened a window for the likes of Jason Terry, O.J. Mayo, Monta Ellis, J.J. Barea and countless others by triggering a moment of hesitation in both defenders trying to stop Dallas' invincible two-man game.

Should they trap the ball-handler, rotate a third man over to Dirk then die when he immediately passes to an open teammate? Should they switch and put a smaller man on the greatest shooting forward who ever lived? Should his defender stick to him like Velcro and encourage a slippery guard to have his way in the paint? There really is no pragmatic solution, as the Los Angeles Clippers quickly realized when Dallas crushed them on Veterans Day.

Watch how Blake Griffin lets Deron Williams waltz right into the paint for an uncontested floater.

Dallas will initiate its offense with a Nowitzki pick and roll, then watch it flow into a chaotic free for all of hellfire and brimstone. The defense has no margin for error and is forced to scramble on an unraveling string. Indecision is fatal.

In Dirk lies a skill set that allows coach Rick Carlisle to get as creative as he wants. One example: Both Williams and Wesley Matthews have a nifty post game. They can back down smaller guards and either draw a foul or force an awkward rotation. This weapon wouldn't be so dangerous if not for Nowitzki's slingshot perpetually locked and loaded behind the 3-point line. Helping is tough, and the Mavericks always have that in their back pocket.

So, any drawbacks? Dallas' offense sparkles with Nowitzki on the floor, averaging 103.9 points per 100 possessions (top 10) against only 97.7 when he sits (bottom five). But the other end of the floor is a disaster zone that could get worse as the season drags on. According to Basketball-Reference, Dallas' adjusted defensive rating (which factors in strength of schedule) is 11th best in the league. That's great news, right? Well, per, the Mavs allow an astounding 13.3 more points per 100 possessions with Dirk hobbling around; they're never worse than when he's on the floor.

It's way too early for on/off numbers to serve as a mic drop, but it's also no secret Nowitzki struggles to defend just about anybody in space, and Dallas' coaching staff has few options outside of dropping him into the paint when they need to stop a high pick-and-roll. So far, Nowitzki has made up for the strain his old legs place on everybody else by somehow rebounding the hell out of the ball. His Defensive Rebounding Chance Percentage -- which measures how many boards he grabs from available opportunities to do so -- compares favorably to Griffin, Nerlens Noel, Derrick Favors and Draymond Green. This is almost definitely unsustainable, but the 18-year veteran is really tall, very physical and does a fairly good job getting to the right spot when an opponent's shot goes up. 

On paper, it's nice and pleasant to daydream about Dirk surrounded by four capable shooters. But in reality, he can't defend players who can drive or shoot. Against the Clippers, he defended DeAndre Jordan. Against the Lakers, he defended Roy Hibbert. Against the Philadelphia 76ers, he defended Noel. This forces Zaza Pachulia to guard the Blake Griffins and Julius Randles of the world, and that's the type of trickle-down effect that will eventually bite Dallas in the butt. Here are three very sad examples.

Sad Example 1:

Jordan Clarkson gives the Mavericks a five-star Yelp review for serving the most delicious German meal he's ever tasted.

Sad Example 2:

Dirk is petrified of getting burned by Kyle Lowry's penetration, so he sinks into the paint before Toronto's point guard even crosses the 3-point line. The result is a wide-open jumper for Luis Scola, who still lives for that shot.

Sad Example 3:

For obvious reasons you should fully grasp after watching what happens, this is the saddest example of all the sad examples:

The Mavericks obviously have no choice but to play a dominant offensive threat who is by far their most important player. The good still outweighs the bad, and Nowitzki's power transcends his usage rate.

As Dirk's colleagues like Kobe Bryant, Paul Pierce, Tim Duncan either fade away or into a dramatically reduced role, the Mavericks are still able to center one of the league's most potent attacks around the best player they'll ever employ.

They don't have the most capable wing defenders, so teams will attack the Mavs by going small more and more as the season progresses -- pushing Dirk either to the bench or up to center -- and Dallas' defensive rating will cave. But when it does, the only thing capable of lifting the Mavericks back up will be Nowitzki's jumper. Tried and true until infinity.

More NBA stories from Sports on Earth

Calmer Cavs, Blatt look to LeBron

Watch Steph Curry score 46 points

Dallas lets DeAndre hear it