MEMPHIS, Tenn. -- The best all-purpose defender in the NBA loves to talk trash. But Tony Allen keeps that in his own locker room. He says nothing to the man he's guarding. Not a word, not whisper, nothing about someone's momma or girlfriend or even what he thinks about their breath. And yes, Allen is usually close enough to tell if they need an Altoid.

"I save my oxygen," he explains, "because I don't want to waste any energy I could be using to play the game."

You wait for him to flash an I'm-kidding smile or jab an elbow into your ribs. Nothing. He can be quite funny and quirky and always seems to be cutting someone up. But about defense? Serious as a stroke.

"I take pride in this," he said. "This is what I do. And not too many people want to do what I do. It's high risk and low rewards. There ain't no glamour, magazine covers, hype and definitely no money."

He laughs about that last part, although he wishes it wasn't so funny. At $3.3 million, he is ranked 194th in salary this season, behind a dozen players who aren't active in the league, behind such immortals as Ekpe Udoh and Joel Anthony. The star players he regularly guards, the Kobe Bryants and Dwyane Wades, pull that in a month. On the Grizzlies, who allow the fewest points in the NBA, Allen gets a few nickels more than the backup point guard, and he doesn't have an extension for next season.

NBA games are won on defense, yet defenders like him don't win at the negotiating table, and sometimes not even in the playing rotation. Allen gets less than 30 minutes a night as a starter mainly due to a shaky jumper. It's a stinging reminder to him that this league values offense and flash no matter what the coaches and general managers say.

Still, it's hard to imagine many players with a heavier load than Allen. He gets the toughest defensive assignment every game, and is asked by Memphis to do the near-impossible: contain a scorer without getting into foul trouble. Allen hasn't fouled out this season. Last week in the same game he had to guard Kevin Durant, the NBA's scoring leader, and Serge Ibaka, who has five inches and 60 pounds on Allen.

In the last month he held Joe Johnson to four-for-10 shooting, Jared Dudley to 0-for-five and Monta Ellis to one-for-14. Kobe got his average of 29 points but needed 23 shots to do it, and the Grizzlies won, so Allen doesn't care.

He gets assigned to sharpshooters, slashers, post-up guys, three-point specialists and quick dribblers and asked to keep them all in check. There are no nights off from defense for Allen, no breathers. Every team brings a guard or small forward who knows how to score and sometimes Allen will even find himself dealing with power forwards and point guards to bail out teammates who can't handle them.

"He reminds me at times of a free safety in football," said Chris Wallace, the Grizzlies' general manager, "with his ability to zero in and focus on the ball. He's all about getting the ball back."

Here's what else sets him apart: Allen owns an extensive video library with footage of almost every guard and small forward and watches it constantly. He calls it "going to the movies" and it's a pregame ritual.

"If you check, my fingerprints might be on every player in the league," he says.

This is a tale of defense and how it's played (and not played) in the NBA. And while we're on the subject, we need to clarify about Allen: there are better shot-blockers and perimeter defenders and on-ball defenders and defenders with quicker hands. He just happens to combine all of the above. And perhaps no one places more importance on defense or treats it like a science as he does because, if not for defense, he knows he wouldn't be in the league. He's an average-sized guard at 6-4 and 210 with average skills who has survived eight years in the NBA with a career scoring average of 7.8 points.

"He has physical gifts -- the guy is strong -- he has a knack for the defensive end and he studies both team and individual tendencies," said Wallace. "If you put those three together you get Tony. You get someone who knows how to play defense with the best of them."

The makeup in the NBA when it comes to defenders usually breaks down three ways:

• Shot-blocking behemoths. Mainly seven-footers with limbs like redwoods and feet of cement, they stay within five feet of the basket. Some are mobile (Tyson Chandler), some not (Roy Hibbert), but all are fairly one-dimensional in this regard -- with the possible exception of Chandler, the reigning defender of the year.

• Thieves. They usually rank high in steals because of sharp anticipatory skills that sometime result in getting burned. LeBron James, Brandon Jennings, Chris Paul and Allen's teammate Mike Conley fit the profile.

• On-ball artists. Their work is mainly done away from the basket, usually on the perimeter, and goes mainly unnoticed because their job is more about stops than steals or blocks. It's how Shane Battier, Metta World Peace, Andre Iguodala and Thabo Sefolosha make their money.

The act of shutting someone down may be the hardest part of the NBA. Rookies and players from Europe adjust slower than most because they're immediately shocked by the speed of the game and often suffer from a lack of strength. They get little respect, at least right away, from the officials. The scouting is so thorough now that secrets are few. Every coach knows whom to exploit and attack and does it with unapologetic consistency.

Finally, a dozen players are almost impossible to guard one-on-one for 48 minutes. Good luck sticking with Kobe and Durant and LeBron and Paul and Carmelo Anthony, and try to avoid fouling out in 10 minutes.

"The prolific scorers are going to score," Allen said. "With me, I try not to beat my head up if a guy scores on me. I know the more I compete and the harder I play, those shots will become difficult for them late in the game. I get judged on getting key stops. If I can get a few key stops down the stretch to help my team win, that won't show up on the scoreboard but it doesn't really matter. I know I did my job."

Raised on the tough side of Chicago, Allen went the unconventional route to the NBA. He didn't play AAU ball. He learned the game on the streets, jumping from playground to playground, and therefore it was no surprise that he didn't have any college scholarship offers. He went JUCO.

"I wasn't one of those fancy scorers or dribblers," Allen said. "I couldn't make a guy look silly on the court. I was just making sure I wouldn't be embarrassed by those type of players and pretty soon I just evolved into this. It's always been a grind for me, even growing up, getting respect and court time. I wasn't a McDonald's All-American. Didn't have no one looking at me. Been a grind right from the start until this very day."

Eddie Sutton tossed him a scholarship at Oklahoma State and told Allen his true skill was hard work. Allen was drafted in 2004 by the Celtics because Wallace, who was then Boston's GM, was sold on Allen's athletic ability and defense. Allen got little burn behind Paul Pierce, and then needed knee surgery in 2007, which is almost a career-crippler for a defensive specialist. The Celtics, wary about his recovery, began to seek replacements and that struck fear into Allen. When he returned, he fell almost out of the rotation. But he had admirers. Teammates rooted for him. During a practice, Allen heard Pierce yell, "just outwork them TA and get your minutes" and Allen adopted that as his motto.

"Playing behind Paul Pierce in Boston, the only way I could get on the court was by playing defense," he said. "I embraced my role and gave it my all. Then I just took it to another level by studying defense."

Some players sit through film sessions, take a few mental notes and when the game starts often forget what they learned. Film and video are sacred to Allen, to the point where it has become an addiction. After nine years in the league you figure he should know everything he needs to know, and you'd be wrong. Or maybe you're right and it's just Allen being addicted to the point of paranoia. He goes a day without watching film the same way you go a day without applying deodorant.

Allen goes the extreme, too. He'll spend 30 minutes watching how a team inbounds the ball. He needs too know who the inbound passer is and the rotations of each of the four opposing players trying to catch the ball. Allen says he's come up with a dozen steals or disruptions on inbounds passes just from hours of filmwork.

He has tape on Kobe going back a few years, but ignores the old footage because Kobe is older now and therefore plays a different game. That's another thing about Allen's movie habits: He's constantly updating, getting a fresh batch of film from Jason March, the Grizzlies' assistant video coordinator, every week.

"I have him break down a guy's last three games," said Allen, "and if the guy I'm supposed to guard had a big game recently I put that on it, too. I just put it all on film and watch it at once."

Allen doesn't grade players or list one as tougher than another. In their own way, they all present a challenge, he says.

"With a guy like Kobe, he's so sporadic in scoring," said Allen. "He might beat you in transition or hit standstill threes so he's hard to guard. It's just a competition between me and him."

There's one type of defense you'll rarely if ever see Allen play: He doesn't make many attempts to draw charges. He thinks that's a lazy way to defend, and puts the referee in position of being judge and jury. Allen would rather control his own destiny. So he concentrates on ball denial first, then tries to force his man to go left or right, whichever is the weaker hand.

"Make it as uncomfortable for him as I can," Allen said.

He has no use for flopping. It's something he can't bring himself to do. He says he has too much pride in his reputation and besides, it just seems wrong. Allen traces this back to playing on the asphalt in Chicago. If he flopped, not only would he receive a busted head, he might be kicked out of the game -- not by the other team, but by his own. Flopping is not what tough guys do.

And Allen, if you polled NBA players, would rate high for toughness, which is both flattering and embarrassing. Seven years ago he was arrested for assault after being involved in a street fight where one man was shot. Allen wasn't charged in the shooting but accused of breaking another man's eye socket. Two years ago he decked former Grizzlies guard O.J. Mayo over a card game. Allen won't discuss any of that, or other stories floating around about his ability to handle himself, though one teammate said cryptically: "Nobody in the league will mess with TA."

He is now 31 and maybe, if you believe the scouts, has lost a step. He's a free agent this summer. He's on a team that, after the Rudy Gay trade, suddenly needs scoring at his position. Memphis could re-sign Allen, for something in the $5 million range, or change course and find some offense at the two-guard spot next season.

"I'd like to stay but whatever happens I'm cool with it," he said. "I'll get what's coming to me. At least I hope. They say defense wins games, right? They say it's all about how you play defense, right?"

He hesitates.

"That means I'll be fine, right?"