Stephen A. Smith explains that the Celtics should be able to beat any team in the Eastern Conference besides the Raptors when Boston is in full form. (1:23)

MARCUS SMART CAN'T remember exactly which game it was because so many of Boston's maddening early-season outings blended together into a collage of misery. What he does recall is that after another confounding loss in which his friend Jaylen Brown submitted another confounding performance, Smart felt compelled to express himself.

"Hey!" he barked at Brown. "We're here for you. We want to help. We want to hear from you."

Silence.

"Say something! Participate with us! Are you with us?"

Brown, his doe eyes widening, looked directly at Smart and nodded.

"It's funny," Smart says now, still incredulous. "He didn't say a word."

Last season, Brown emerged as a budding two-way talent poised to make the jump to stardom. A gruesome injury to Gordon Hayward and knee woes that later shelved Kyrie Irving provided Brown with unexpected prime-time minutes that he put to good use, emerging as one of the team's most dynamic defensive players while shooting 39.5 percent from behind the 3-point line.

In the postseason, Brown became the youngest player in Celtics history to score 30 points in a playoff game. In the offseason, Brown couldn't wait to build on that foundation, assuming a starting role in a stacked lineup that was anointed as the team to beat in the East.

Instead, the Celtics staggered to a 10-10 start. And nobody disappointed more than Brown.

According to ESPN Stats & Information, with Brown on the floor through those first 20 contests, the Celtics averaged 100.4 points per game, which would qualify them as the worst offensive team in the league. With Brown off the floor, the Celtics ranked 10th offensively. Brown's turnovers ran neck-and-neck with his assists; he was shooting 25.3 percent on 3s, ranking him 122nd out of 123 players who attempted at least 75 shots. (Last season, Brown's 39.5 percent shooting landed him 37th among qualified NBA 3-point shooters.)

Defensively, the numbers also dipped. Per Second Spectrum, among the 204 players to defend at least 20 direct isolations, Brown was tied for 150th, at 1.04 points per direct iso defended. (Last season, he was tied for 73rd, allowing 0.88 points per direct iso.) In those first 20 games, Brown was the closest defender on 204 shots and contested 149, or 73 percent, of them. (Last season, according to Second Spectrum, he contested 78.4 percent of such shots.)

Opposing teams have privately used words such as "disjointed" and "detached" to describe him. When the season's first Real Plus-Minus ratings were released, Brown ranked 417th out of 430 players. The question "What's wrong with Jaylen Brown?" became a leaguewide referendum.

"Oh, you noticed?" Brown says with a wry smile.

The Celtics are hoping that a move to a reserve role can kick-start Jaylen Brown's season. Maddie Meyer/Getty Images

ON NOV. 24, Brown injured his back against the Dallas Mavericks. Two days later, Boston inserted Marcus Smart into the starting lineup and won six straight. Brown returned after three games but has been relegated to a reserve role. He has handled his demotion without rancor or complaint, but don't misconstrue that as a sign that he has accepted his new role.

Despite the analytical scrutiny, the incessant trade rumors that have swirled around him, the "tough love" he has endured from teammates and the realization that his own lofty goals will have to be tempered for now, Brown says he will continue to fight for himself and his firm belief that he's an NBA starter.

"It's probably been the hardest thing I've had to deal with so far in my career," Brown says. "Just coming from a position where you had so much responsibility, and now that responsibility is lessened. Expectations have been raised, but your responsibility goes down, so it's hard to reach those expectations when you aren't being asked to do as much.

"It's been a challenge. It's going to continue to be a challenge. It's all about your mindset, so that's what I'm focusing on."

In his three games as a reserve, Brown has appeared more aggressive, averaging 21 points and five rebounds. He has attempted 17 free throws (5.67 per game vs. 2.25 as a starter) and is shooting 56.8 percent from the floor. Brown, who is often so quiet in the locker room, is aware that his docile demeanor could mask his competitiveness.

"That's a question that others can answer better than I can," Brown says. "I've been misinterpreted before. Sometimes silence is looked at as something different than it is."

It is absurd to lay all of Boston's early-season stumbles at the feet of Jaylen Brown. He is clearly not the only one who has struggled. Consider Hayward's ongoing mental and physical battle to return to form, as evidenced by his hesitation to penetrate and draw contact and moments when he appears as though he's running in a vat of oatmeal.

Terry Rozier, who has chafed at a reduced role that has him averaging 22.8 minutes per game, has also been inconsistent. So, at times, has Jayson Tatum, although his electric offensive skills have kept him in the rotation.

"So here's my reality: I'm an NBA player on the Boston Celtics, a team that has a chance to compete for the NBA championship. Nothing else really matters."

Tatum drew the ire of coach Brad Stevens early in the third quarter of a pre-Thanksgiving loss to the New York Knicks -- a debacle that might well have been the low point of the Celtics' season -- when he settled for a long midrange jumper after Stevens vehemently stressed at the half that he wanted his team to drive the ball and take high-quality shots. The decision landed Tatum on the bench just 1 minute, 10 seconds into the quarter. Tatum pointedly stood outside the huddle during the next two timeouts while assistant coach Jay Larranaga attempted to re-engage him. When Stevens called Tatum's name later in the game, he helped lead a late-game charge that fell short.

This, undoubtedly, is the kind of reaction the Celtics hope to get from Brown as he works to regain his mojo.

When Irving publicly gave a thumbs-up to the current starting lineup that includes Smart, Al Horford, Tatum and Marcus Morris, it raised eyebrows regarding his relationship with Brown. Kyrie says it's simple: As the team leader, it's his job to get the most of each player, and Brown, at times, has come up short.

"I have such high expectations for a guy like Jaylen, knowing how smart he is off the court, knowing his intellect, how he likes to be challenged," Irving says. "On the court, you just know there's so much more for him. You can see how much better he can get.

"I don't think Jaylen has ever been challenged in this way. When you're challenged sometimes, and you've been only doing it for three years, you can question a lot of things. You question yourself, and your confidence wavers because everything you've been doing up to this point has worked. You're used to doing little things to get you out of a rut, but suddenly that's not happening.

"You find yourself in a situation where every single day you are demanded to be great. That's a hard journey for anybody in this league, and to have that much talent and not be able to showcase it, I'm sure it is tough on him.

"I definitely understand it. I'm empathetic, and I'm also patient."

But he's also unafraid, he says, to get in Brown's grille: "I think he deserves that. In my career, I've had the opportunity to play with another great player who demands greatness out of you every single day. That comes with certain expectations. Sometimes you don't know exactly what those expectations are until you experience them. And that's what Jaylen is dealing with now.

"It's not about how many shots he's making or percentages or stats or anything like that. Now it's about, 'How do you get out of your own way to become the best version of yourself in an environment with other great players?' You're not in an environment where we can wait around for you. You're not surrounded by decent players who you will automatically play over, no matter how you perform. Now you have to work because other guys are putting in their work, trying to accomplish a goal bigger than themselves.

"The beautiful thing about Jaylen is he's smart enough to figure this out. He's in a transitional year."

Jaylen Brown says he will continue to fight for his firm belief that he's an NBA starter: "It's all about your mindset, so that's what I'm focusing on." Frank Gunn/The Canadian Press/AP Photo

PRESIDENT OF BASKETBALL operations Danny Ainge says he knew there would be months such as this. He was aware that issues existed in meshing his deep, talented roster, and he anticipated that there would be angst as young players tried to "move up notches" on the roster.

"I think individuals and teams sometimes have different expectations from reality," Ainge says. "Sometimes it takes a while for reality to hit. You can change the expectations by playing poorly, or you can elevate expectations by playing well."

Ainge played on multiple championship teams that were steeped in talent and depth. But his reality was that guys named Bird, Parish and McHale were always going to be ahead of him.

"I think in 18 years in professional sports, I had the role I really wanted maybe five out of those 18 years," Ainge says. "But you have to make the best out of what you have.

"Unless you're the elite, elite superstar in this league, you don't always get the role you want, so you have to make the most of whatever you have."

Coach Brad Stevens, who puts great stock in analytics, says Brown's offense will come, and his current defensive numbers don't tell the whole story. "We're asking Jaylen to guard a lot of different guys at a lot of different positions, from Tim Hardaway with the Knicks to Blake Griffin on a day-to-day basis," Stevens says. "Within all of our schemes, with all the things we've been doing, I actually think Jaylen's gotten better. He's doing a lot of different things, both on and off the ball. That's why I don't get caught up too much in the individual defensive numbers."

Ainge, for his part, insists that the game is slowing down for Brown, that he's making even more strides defensively and that his critics are putting too much emphasis on his shooting.

"I'm not worried about Jaylen at all," Ainge says. "He's a terrific player. Give me 80 games. I might care by the time we get to the playoffs, but the kid is 22 years old with a ton of upside. The criticism has been ridiculous."

FOLLOWING THE KNICKS game this past Thursday, when Brown submitted a tidy 21 points in 25 minutes on 7-of-10 shooting (including 7-of-9 from the line), he didn't pound his chest or scream expletives in the postgame locker room. Yet, Smart says, there was a bounce in Brown's step that they haven't seen much this season.

"The last thing we wanted was for Jaylen to get in his own head," Smart says. "Like we told him, 'Listen, nobody's gonna feel sorry for you in this league. Nobody. All of us were stars at one time, the best players, who never came off the bench. And most of us have had to adjust. You can't let that bother you because people are out there just waiting to pounce on any little crack in your confidence.'

"He knows we're on him because we care. There's no malice in any of it."

"I don't think Jaylen has ever been challenged in this way. When you're challenged sometimes, and you've been only doing it for three years, you can question a lot of things."

In the meantime, Irving says, he's learning about this leadership stuff on the fly.

"I realized I had no idea what I was doing to begin this season, either, in terms of what we looked like, the plays we'd be calling, my relationship with Coach Stevens, my relationship with every guy on this team," he says. "It's going to be unique with each one of them.

"I'm accountable for these guys to play at a certain level every single night and demand that out of them. If that comes with being in some guys' faces and making them feel uncomfortable and not being well received or not well liked, that's just what it comes down to. I know what it's like to be on that stage and to play against a juggernaut of a team, and I know the little things matter. You can't lose your sense of self in a matter of a moment. You can't be soft or fragile on the way to that championship because guys will be coming after you. So why not challenge our guys during the season to prepare them for that?"

Brown says he is unfazed by Irving's and Smart's motivational tactics. His three-game absence afforded him some time to reflect, watch film and identify why he was putting so much pressure on himself.

"What's hard to do is to separate what's real and what's not real in what you feel," Brown says. "We all have emotions, we all have things that we think are happening, whether they are happening or not.

"So here's my reality: I'm an NBA player on the Boston Celtics, a team that has a chance to compete for the NBA championship. Nothing else really matters.

"Right now, people are throwing out all these numbers, these stats, and they are saying this, saying that. I have unwavering faith in my ability, and I believe our coaching staff does, too. If anyone can handle this, I can. I've been through a lot in my short life. I'll be all right."

Gordon Hayward and Jaylen Brown have been slow to find their footing in Boston's stacked lineup. Adam Glanzman/Getty Images

SO WHAT'S WRONG with Jaylen Brown? Weeks ago, when Marcus Smart challenged Brown in the locker room, he was, in his own way, posing that question. Today, when Jaylen is asked about that encounter with Smart, he listens and acknowledges that he remembers the exchange. Then he explains why, at the time, he said nothing.

"I try to keep an even keel," Brown says. "Whether it's bad or it's good, I don't want to get too high or too low because that's how you end up in trouble."

Today, Brown says he's back on track. He says he will exploit opponents with his cat-quick first step and be more aware of passing lanes when he draws a crowd.

And yet, there he was in the waning seconds of the second quarter against the New Orleans Pelicans on Monday night, plowing into the key as the shot clock dwindled with three players around him, while Marcus Morris, who already scored 12 points in the opening half, stood open behind the arc. Brown kicked it to him with a wild pass that was much too late, and the shot clock expired before Morris could even get a handle on it. The exasperated veteran slammed the ball, and Brown received a tongue lashing from Smart all the way to the locker room.

"Morris was pretty hot, and he's wide-open," Smart said after the game. "We've gotta make that pass. We're just letting [Jaylen] know, 'Keep it moving. Get it back. Don't let the ball stagnate.'"

Brown vows to be better. He says he'll track the league's best offensive players with a doggedness that will return him to the upper echelons of the defensive rankings. He'll prove to Kyrie Irving and the rest that he belongs in that starting five.

"This is a story that's being written," Brown says. "There's going to be highs and lows. Everything that's happened, the energy will change.

"Come back in two weeks. The numbers will be different, and so will I."

ESPN's Tim Bontemps contributed to this story.