Gregg Popovich's wrinkles are not just a sign of an aging man; they represent the hard work of a long and successful coaching career.
Ten division titles, five conference championships and four rings later, Popovich is considered one of the best coaches in the history of the NBA.
On the football field, Bill Belichick has led the New England Patriots to the pinnacle of the NFL multiple times, keeping the Pats perennial contenders.
Since both San Antonio and New England have been very successful franchises, does that mean the coaches should be compared with one another? Popovich and Belichick have each suffered only one losing season through 17 and 13 years with their respective teams.
But considering how Pop and Belichick made it to where they are now, it becomes evident how similar the two men really are.
Militaristic. Sacrificial. Dedicated.
Each one of those words directly applies to both Popovich and Belichick, and their upbringings have much to do with that.
Popovich graduated from the Air Force Academy in 1970 and served his mandated five years in the Armed Forces, while Belichick spent his early years at the Naval Academy, because his dad, Steve, was an assistant coach and scout for the Navy football team.
Former Spurs' guard Brent Barry called Pop a "master communicator" on NBA TV, which is clearly evident when the coach chides his best players—like when he chews out Tim Duncan and screams at Tony Parker.
Steve Belichick had a sizable impact on Bill's mentality and philosophy, teaching his son how to interact with his teammates, as noted in the accompanying ESPN video.
"You work with your teammates to get the job done, and you always put them ahead of you...your teammates are more important than you are. You sacrifice for them, and you don't let them down. That's an awesome lesson that has affected my entire life and my coaching philosophy."
To say these men paid their dues is perfectly accurate.
After leading for D-III Pomona-Pitzer for seven years, Popovich was a volunteer assistant under legendary coach Larry Brown at the University of Kansas. Pop followed Brown to the Spurs and spent four seasons as an assistant before eventually taking the reigns as San Antonio's general manager in 1994.
At 23 years old in 1975, Belichick took a $25-per-week position as an assistant's assistant with the Baltimore Colts. He then served in various positions with the Detroit Lions, Denver Broncos and New York Giants before taking the reins as head coach of the Cleveland Browns.
Popovich and Belichick were dedicated, learned the game and rose to the top of the NBA and NFL.
Interaction With the Media
Popovich is often frustratingly vague when talking to sideline reporters, giving logical yet disappointing one-word responses to well-worded questions.
Strangely enough, interviews with Popovich are among the most captivating 30 seconds of television.
His lack of "good" or substantive answers even led to TNT's David Aldridge just asking one of his allotted two questions—much to Pop's probably welcomed surprise.
Similarly, Belichick makes his press conferences equally "boring." He continuously answers questions by almost robotically spewing out the most general answers to a wide variety of inquiries.
As seen in the below video, Belichick will often say "we made enough plays to win" after a victory, and "we didn't make enough plays to win" following a loss.
There are no excuses, no "what ifs" or "if onlys," and no rants; Pop and Belichick simply want to get back to coaching.
Both men pride themselves on putting excellent teams on their respective playing surfaces, and they are extremely cognizant of not tipping off their team's plan of attack.
Public opinion of the coaches basically revolves around something to the tune of "stubborn," "stalwart" or "senile." But neither leader is worried about the public's perception of how they work and they essentially become even more intriguing in that way.
And though it is impossible to know what's actually on their minds, the coaches sure have been successful, largely due to their knowledge of the game.
As mentioned earlier, Popovich has led the Spurs to four NBA championships in 1999, 2003, 2005 and 2007. Last season, San Antonio was one shot away from winning another, but what is nearly as impressive is Pop's rather impressive coaching tree.
Future NBA head coaches including Doc Rivers, Avery Johnson, Vinny Del Negro and Monty Williams played under Pop. Four more former assistants became NBA head coaches: Mike Brown, Jacque Vaughn, Brett Brown and Mike Budenholzer.
The NBA's front offices have seen their fair share of Popovich disciples, as NBA general managers Danny Ferry, Rob Hennigan, Sam Presti, Kevin Pritchard and Dell Demps are in charge of various franchises.
New England has won the AFC East in 10 of the last 12 seasons, as well as five conference championships and three Super Bowls (2001, 2003 and 2004) during Belichick's tenure.
Belichick, too, has aided the growth of many recognizable football coaches. Eric Mangini, Jim Schwartz, Romeo Crennel and Josh McDaniels each held positions under Belichick.
Also, well-known college coaches, including current Penn State coach Bill O'Brien, longtime Iowa head coach Kirk Ferentz, former Notre Dame and current Kansas head coach Charlie Weis and defensive mind Al Groh served on Belichick's staff at one point.
Oh yeah, and there is some guy named Nick Saban. Rumor has it he's been pretty good at LSU and Alabama, winning four national championships (and creeping up on a fifth) on opposite ends of a two-year stint with the Miami Dolphins.
Success is usually measured in championships—and often rightfully so—but Pop and Belichick both add to their legacies with the players and coaches they have taught.
Neither San Antonio nor New England were bottom feeders in their sports, but Popovich and Belichick have turned their franchises into elite organizations.
So, is Popovich the NBA's Bill Belichick?
The Spurs had never won an NBA championship, let alone a conference title. The Patriots, on the other hand, had appeared in two Super Bowls but similarly had not won a championship.
Four and three league titles later, respectively, Pop and Belichick demand respect and attention from every team in their league whenever San Antonio and New England appear next on the schedule.
Most importantly, though, Popovich is setting up the San Antonio organization to succeed when he finally retires—which should line up with Duncan untucking the jersey for the final time.
Belichick has his esteemed veteran in quarterback Tom Brady, and as long as the University of Michigan product is on the field, the Pats will contend for the Super Bowl.
Both coaches grew up with military values, paid their dues, succeeded in their sport, passed on their knowledge to future leaders and share an entertaining disdain of questions. Popovich and Belichick are one and the same, cut from the same cloth.
And we can only hope the duo sticks around the NBA and NFL for a few more years.
Follow Bleacher Report NBA Writer David Kenyon on Twitter @Kenyon19_BR