As Dirk Nowitzki heads into his 16th season, he's coming off his lowest points per game average since his first full year, saw a dip in rebounding and health is now becoming a factor. ESPNDallas.com will explain five reasons why it’s too soon to say Dirk’s demise as an elite player has arrived.

A big man in his mid-to-late 30s will continue his pursuit towards another NBA championship. And no, it's not Dirk Nowitzki. Tim Duncan is showing that an older big man can still dominate the game as the 37-year-old has averaged 17.8 points, 9.2 rebounds and 34.4 minutes during the Western Conference playoffs. Those numbers are hovering right around Duncan’s season average, which is why he earned first team All-NBA honors.

At age 37, Spurs center Tim Duncan was named to the All-NBA first team and is averaging 17.8 points, 9.2 rebounds and 34.4 minutes during the Western Conference playoffs. AP Photo/Eric Gay

Duncan provides an example of a prolific big man who has dealt with injuries but has been able to sustain a level of excellence over a sustained period of time. When you look at the comparison, it suggests that Nowitzki still can have plenty left in the tank if he follows a path similar to his San Antonio counterpart. At 76 games, Duncan has actually played nearly one season’s worth of basketball more than Nowitzki when it comes to playoff basketball. And he's three years older than Nowitzki.

Both Duncan and Nowitzki are gym rats who have taken care of their bodies through proper nutrition, have slimmed down to sustain the grind of a season and are truly motivated to win. Whether it is Duncan's attack via fundamentals or Nowitzki's jazz-like approach, both have games that get the job done.

It appears Nowitzki is willing to follow Duncan's lead when it comes to his bank account. In what could be his final contract, Duncan re-signed with the Spurs in the summer of 2012 for a three-year deal worth $30 million. The final year of his previous contract had him earning $21 million. Expecting to be the second-highest paid player in the league for the 2013-14 season, Nowitzki has already said he’s willing to take a “significant pay cut” next summer.

"At this point of my career, it's all about competing and winning," Nowitzki said in mid May. "It's not about money. Obviously, [Mark] Cuban took care of me for a long, long time. I always tried to pay him back by playing hard and being here for this franchise, so I don't think we're going to fight over money. I want to compete over these last couple of years. That's going to be the goal."

The big difference is that Duncan has had help staying fresh over time as the Spurs have surrounded him with top-notch support. Both Tony Parker and Manu Ginobili have stepped up at different times during the Duncan era. On top of that, the Spurs are also starting to develop a new crop of studs in Kawhi Leonard and Danny Green.

It is a given that Dallas needs to load up this summer and start finding more weapons to play alongside Dirk. While it’s still one year away, Nowitzki is showing that he’ll be proactive. The space will allow Dallas to continue their plan to get the team back to contender status.

At 37, Duncan is looking to get another championship ring. Age is just a number. Like Duncan, Nowitzki can use that to his advantage.

Bryan Gutierrez currently covers the Dallas Mavericks for The Two Man Game, an ESPN affiliate blog on the TrueHoop Network. Gutierrez, who has covered the Mavs since 2010, studied journalism and psychology at Texas Tech University.