To understand just how valuable Bryce Harper has been to the Washington Nationals this year, consider this: On Sept. 3 against the Atlanta Braves, Harper -- the 22-year-old outfielder who, in his fourth season in the big leagues, is the clear front-runner for National League MVP -- led the Nats to a 15-1 rout by scoring four runs and driving in another ... without even swinging. He came to the plate four times and walked four times. In total, he saw 20 pitches and swung at exactly zero of them. The following day, in his first at-bat, he finally saw a strike -- and hit it out of the park. Just as he did the day after. And the day after that.

"It reminds you of Barry Bonds," said Braves first baseman Freddie Freeman. "Obviously he's not hitting 70 home runs. But he's gonna take his walks and take his walks. Then he gets one pitch to hit, and he hits it. That's what he's doing this year, and he's doing it every single day. It's incredible to watch."

Talk to National Leaguers who play with and against Bryce Harper and it's clear they agree on one thing: He's this year's MVP. G Fiume/Getty Images

If it's anybody other than Harper, that dust-up with teammate Jonathan Papelbon in the Nationals' dugout on Sunday isn't the firestorm it has become. Instead, it's the talk of the game, made monumental by the measures of Harper's historic season. Through Tuesday, he led the majors in slugging, OBP, OPS and WAR and the NL in batting average, runs and home runs. Papelbon took all that on when he confronted his teammate. Talk to National Leaguers who play with and against Harper, and it's clear that he has become more than just the most valuable player on his team this season, and it starts with the evolution in his approach at the plate in 2015.

Fredi Gonzalez, Braves manager: That four-walk game against us? A year and a half ago, he goes 0-for-3 with a couple groundouts and a walk. I'm not kidding. He would've expanded the strike zone and swung at everything -- the back-foot slider, the change, the fastball out of the zone. But now we're not seeing that. He's locked in, and he's sustaining it.

David Wright, Mets 3B: He's starting to understand what pitchers are trying to do to him. He's willing to take his walks in situations where pitchers are trying to make him chase and get himself out. That says a lot about going from how young he was to now you watch him play and he just looks like a veteran.

Rich Schu, Nationals hitting coach: When we got him, I was the minor league hitting coordinator for the Nationals. I roved all the way from rookie ball to Triple-A. As soon as you saw Bryce take his first swings in pro ball, you knew he was special.

Tyler Moore, Nationals 1B/OF: Back when we were in Double-A, nobody could hit the ball off the tee from home plate over the center-field fence. Well, he gets up there the first time and hits it out. That night, he hits a 3-2 curveball out to dead center. It was pretty special to watch.

Drew Storen, Nationals P: He's got an unbelievable eye. As a pitcher, you try to expand the strike zone and miss the barrel. But he's letting guys come to him and make mistakes, and he's capitalizing on them.

Schu: What he's doing now is what he was doing at a younger age in the minors -- controlling the strike zone. But as he got to the big leagues, he started trying to do too much. In spring training this year, he really started slowing down. Now he's back to relaxing and letting the game come to him, not trying to do too much.

Clint Robinson, Nationals 1B: When I was 22 years old, I had no control of the strike zone.

Gonzalez: He was really, really hot coming out of spring training and [by the end] of April, he was unbelievable. When we came to Washington in May for the first series [in D.C.], his first at-bat, we threw a couple pitches where the year before he would've swung over it, or swung at it out of the strike zone or out of control. He didn't bite. I turned to [Braves pitching coach Roger McDowell], and I went, "Oh, s---."

This year, Harper has recorded 10.1 WAR -- nearly double his previous season high, which he put up his rookie year. Alex Brandon/AP Images

Freeman: Against Ross Detwiler (on Sept. 5), he got to 3-0 and obviously took the next pitch even though it was right down the middle. The 3-1 pitch was right on the outside corner, and he still took it. Next thing you know he gets a pitch that's middle in and hits a double, left on left against a guy throwing 94-mile-an-hour sinkers. That's after hitting a back-door cutter off Shelby Miller for a home run and another back-door cutter off Shelby for a double.

Shawn Kelley, Padres P: We were down big and I needed to eat innings for the team [in a 10-0 loss on May 15]. I just assumed I could flip him a slider. So I threw him a get-me-over slider [on a 2-0 count], but he wasn't having anything to do with it. He crushed it into the bleachers. The thing that separates guys like him and [Mike] Trout and [Miguel] Cabrera is that they don't just hit mistakes.

Storen: He's hit some balls out that are just good pitches. Like the one he hit off Rubby De La Rosa in Arizona [on May 12]. It was a slider down and away. He just pretty much one-handed it. De La Rosa was just like, "Really? C'mon!" It's the kind of pitch that maybe a good hitter gets the bat head on. But to hit a home run on it? That was incredible.

Moore: This game is all about failure. He's learning to accept that, and that's really helped him. He's such a good athlete, he expects the best for himself, but obviously you can't get hits every time. When he doesn't get too down on himself after popping out or something and keeps his composure, his next at-bat is a lot better. And this year he's matured into that person. It's been impressive to watch.

Gonzalez: He's not chasing like a wild mustang, the way he was the first couple years. That's a byproduct of playing every day the last three and half years. That young man has done [a] helluva job growing up in [the] major leagues in the eye of [the] media. Coming up at 19 years old, that's not easy. Now he's an old guy at 22. The sky's the limit with him, really.

Bryce Harper: I'm still gonna yell at umpires. That's just how I am. That's the fire, and that's how I am. It's zero to a hundred. I guess that's bad, and hopefully I can stay in as many games as I can. But if it's 3-2 and we're in the bottom of the ninth and we've got one out with second and third and a guy rings me up, I'm going ballistic. That's just how it's gonna be.

Harper hasn't had a bad season since he came to the majors, but this is the first year many feel he has really lived up to his superstar potential. Part of that is patience, he says, sure. But a bigger part is that, for the first time, he has been able to play an entire season.

Harper: The thing is, I [had success] in high school, I did it in college, I did it at every single level in the minor leagues. But I haven't been healthy. Everybody asks me what I'm doing different or did something click. I'm just healthy. This is the type of player I have been and this is the type of player I want to be.

Schu: He's stayed injury-free. He had that thumb thing last year, probably overcompensated and tried to do too much. Coming back from injury, trying to get everything back at once. He plays so hard and gets banged up, but this year he hasn't had that nagging injury.

Harper: I still feel like I play as hard as I can as much as I can. I really pride myself on that, but there are certain situations where you pick your spots and you know when you need to lay out. There was a ball down the right-field line when Papelbon was pitching [on Sept. 14]. I [slid] and caught it. There are certain spots where you pick and choose where you want to do that. That just comes from talking to other guys, talking to J-Dub [Jayson Werth], talking to [Nationals manager Matt Williams], and figuring out what I should do.

The dugout fight between Harper and Jonathan Papelbon started a firestorm of opinions that dominated the headlines for days. Greg Fiume/Getty Images

Last weekend's dugout altercation with Papelbon happened after the closer chided Harper for what he apparently considered a lack of hustle on a flyout. Both said they had put the public scuffle behind them by the end of the game, but it raised questions about the team's chemistry and Harper's role in the clubhouse, and reignited an old debate about Harper's "attitude."

Robinson: People saw what happened in the dugout, you make your own opinion. I think [Harper] did a good job of saying what he's going to focus on for the rest of the season and that's it. Off the field, I don't think of Bryce as a 22-year-old. He doesn't look like a 22-year-old. He doesn't act like one. He's a grown man who's got a good head on his shoulders and he shows it.

Casey Janssen, Nationals P: As a clubhouse leader, I don't know if it's [Harper's] time yet. I think he's getting valuable experience along the way, but I would think with the personnel we have in this clubhouse, the payroll we have in this clubhouse, I don't think that's his job yet. If he were to try and be that, I think he would be stepping on other people's toes that have the clout and have the years of experience, the salary that goes along with that job. You've got J-Dub, who has I don't know how many years in the league, tons of playoff experience, World Series. There's Max Scherzer, ace of the staff, big salary guy, has pitched in the playoffs and won a Cy Young. To be the main guy of the clubhouse, I don't think it's his time yet. That's not a slight on him at all. It's just we have other guys in this room that, quite frankly, are probably getting paid to be that leader.

Ryan Zimmerman, Nationals 1B (in an interview before the altercation): When you're young and come up here, you say you're going to play hard every day. You're gonna pop up to the infield and be on second base every time. I'm not saying you don't need to hustle, but you have to learn how to sustain over six months. A guy with his talent level, and how much he's learned over the past three years, if he plays 155 games every year, there's going to be some special numbers that he puts up.

Tony Tarasco, Nationals 1B coach (before the altercation): He's an emotional guy. Sometimes he wears it on his shoulders. But he's been able to contain it and use it in the proper way. With emotion you're going to have ups and downs, you're gonna see it more than you would on stone-cold Paul Molitor. That's what's beautiful and exciting about this game.

Robinson: He's not the guy that we have to turn to for wisdom. There are older guys in the clubhouse for that, and I think he understands that. He's done a really good job of just putting his head down and going out and playing every day. No matter what anyone wants to say about the lack of hustle or anything, if you watch Bryce day in and day out, you know he plays the game the right way. He gets after it. He'll play 150-something games this year. That's a lot of games. I don't care how young or old you are, that's tough to do. Physically and mentally, he's mature beyond his years, for sure.

Janssen: People have to realize he's growing up in the biggest spotlight. What comes with being on commercials and being on the cover of ESPN [The Magazine] is that you're under a microscope your whole career. Fair or not fair, it's what's given to him. It makes everyone talk about him, good or bad. But does he have the ability to become a clubhouse leader and on-field leader? Absolutely. What I knew when I was a rookie compared to what I know now -- the words you choose, the interviews you accept or pass off -- it's all learning. I still think he's one of the best players in the league. Glad he's in our clubhouse.

"His game has developed into one of the best all-around games in baseball," David Wright says. Evan Habeeb/USA TODAY Sports

One of the few sore spots in Harper's season has to be that, despite his MVP-caliber numbers, the Nats will miss the playoffs in a year in which they were expected to contend for a World Series title. Harper, then, won't have a chance to build on his great performance last October, when he put up an 1.251 OPS in the postseason. Still, despite his team's struggles this season, he has delivered in some of the Nationals' biggest moments.

Robinson: He's one of the ultimate game changers in baseball. He can carry a lineup by himself.

Janssen: The Fourth of July game, he had this crazy-looking bat that looked like a trophy. It was red, white and blue, with stars and stripes. It had some kind of mural of the D.C. skyline. His first AB against [Giants ace Madison] Bumgarner, he hits a homer. Left on left, 11 a.m. game, [close to a] sold-out crowd. A lot of things weren't stacked in the hitter's favor.

Robinson: To be able to lock in like that for a day game? Getting to bed earlier than 2 a.m. is a rarity just because you're so juiced up from adrenaline and all that. It's a quick turnaround -- that's why so many vets take day games off. You're playing a full nine just 12 hours after you ended one. It was like, Jesus -- talk about being locked in.

Harper: Being able talk to Matt [Williams] about hitting every single day has been huge. He's so smart about hitting and [your] mentality at the plate and what pitchers are going to do. Don't get caught up so much in what they're going to do and just do it yourself. Really try to get your pitch, drive your pitch, take your walks, and have the faith in the guys behind you to get things done. If they throw me a ball, I'm not going to swing. If they throw me a strike, I'm going to try to do what I can. I'm not going to try to hit homers, but try to get as many hits as you can in a game, and your homers will come.

Freeman: He didn't even swing the bat against us and took four walks. The fourth time, when he came down to first base, I said, "That's your fault," because he took a 3-1 heater for a strike. He was like, "It wasn't where I was looking." I was like, "What do you mean? It was a strike!" I would've swung at that 3-1 pitch and probably fouled it off -- that's why he's hitting .340 and I'm not. The next day, he walks again and homers. I was like, well, he knows what he's doing.

Robinson: Against the Marlins [on May 6], he had that three-homer game. And they weren't cheap ones. These balls were hit like 400-plus feet. I'm talkin' about bomb home runs, like upper deck. It was just like, wow, that was impressive. And I think it was on three different pitches. That's when I was like, "Man, this kid is pretty special."

Janssen: The balls he hit [against] Miami were impressive. They looked like golf balls going out of there. The guy's impressively only 22 years old. His walk-up song says it all: "The Best is Yet to Come."

Freeman: He's already on the cusp of being one of great players in the game. He's a special talent, special player, and he's putting it all together. Usually that happens to guys at 27, 28, 29, 30, and you have a six- or seven-year window of being one of best players in the game. He's already hit that window at 22. So this could last a long time.

Harper leads the NL in batting average, slugging percentage, on-base percentage and home runs. Brad Mills/USA TODAY Sports

The stats say enough, but the Nats are sitting out the postseason. Should Harper's monster year outweigh the BBWAA's tradition of handing out the MVP award to a playoff-bound ballplayer?

Zimmerman: He's obviously had an unbelievable year -- his on-base percentage, a hundred-some walks, hopefully he'll get to 100 RBIs, obviously 40 home runs, I think he's pretty close to 40 doubles as well, has a chance to win the batting title ... it's a pretty special season. It speaks volumes to what he's been able to do with all of us getting hurt, with the numbers he's put up and the attention that he gets, and deservedly so.

Wright: His game has developed into one of the best all-around games in baseball. It's been impressive for me to see a younger guy that had all the tools and makings of a superstar become a superstar with the maturity and plate discipline and just knowing how to play the game.

Schu: If he was in Double-A, he'd be a hot prospect. Instead, he's a superstar.

Zimmerman: Where would we be without him? I'm biased, but what he's done all year, seeing how many opportunities, or lack of opportunity, he gets to do what he's done, is pretty special. Not taking anything away from [Nolan] Arenado and [Paul] Goldschmidt -- and I don't count pitchers, I think that's ridiculous; you can't be an MVP if you play once every five days -- but I think he deserves it.

So we asked Harper: Who does he think should win this year's MVP?

Harper: Nobody. Abstain. I don't know. We'll see at the end. We'll see at the end.