Only one thing will make this season a success, and no, trading Nate Robinson doesn’t count. The Celtics will either win an NBA championship or enter the offseason as a failure, with an NBA lockout likely and no promise the Big Three will ever play like the Big Three again.

In retrospect, that’s why I responded so harshly to the Kendrick Perkins trade. With Perkins as the starter, we knew the Celtics could win a championship. They’d already won one, and as Doc Rivers has said, the starting five with Perkins was never beaten. They won one title, lost in the Eastern Conference semifinals when Kevin Garnett got hurt, and lost in Game 7 last season after Perkins went down in Game Six. With Perkins as a starter, the Celtics were 7-0 in playoff series; 7-0-1 if you count the Lakers series as a tie.

We had faith in Perk, because we knew everything he was about. He was going to scowl, throw elbows, notch a technical foul once every three or four games, limit the opposition’s best post player (unless said post player was Andrew Bogut, who Perk never quite figured out), hold his own on the glass, scowl some more, make a few short fadeaway jumpers over his left shoulder, take his sweet ass time while releasing layups, and bring a physicality rare in the NBA. With Perk, the Celtics intimidated other teams. With Perk, the Celtics’ starting five proved it could win a championship. Without him, well, questions needed to be answered.

Can Nenad Krstic keep the defense functioning at a similar level? Can Shaq ever return to health? Who becomes Boston’s enforcer when the playoffs come and another team lowers the boom with a hard foul? Can the Celtics still defend Dwight Howard one-on-one? Does the way Howard’s teammates have played make the previous question a moot point? Can the Celtics still punish Miami inside? Do they have enough to limit the Lakers if they see them again? Is Jermaine O’Neal even alive? Are the Bulls as good as they’ve looked during the regular season? Can the Celtics handle them?

Many of those questions, of course, existed even when Perkins still wore Celtics green. I understand that. Perk’s presence did not change the O’Neal brothers’ health. It did not change that the Bulls are now a legitimate threat. Hell, Perk was injured, and his questionable health only would have added more question marks. Still, there was something comforting about knowing the Celtics had been there before as a unit. That they’d won with Perk as their starting center. That they were still undefeated in the postseason with their starting five intact.

That same feeling of familiarity no longer exists. Even now, after last night’s dismantling of Milwaukee and a mostly-impressive start to the Krstic/Green era, the new-look Celtics have yet to play a contender. They haven’t played LA, Miami, Chicago, San Antonio, or even Orlando or Oklahoma City. We don’t know how the newcomers’ success will translate against the league’s best. We don’t know how they will respond to the playoffs, and, really, neither do they. Green has played in one playoff series during his career, and Krstic has never advanced past the second round.

In short, we don’t know nearly as much about Nenad Krstic or Jeff Green as we knew about Kendrick Perkins, nor do we know as much about the new-look Celtics as we did the old-look Celtics. That lack of knowledge leaves us with a hint of wariness, of course. But as we learn more about Green and Krstic, as we learn more about the new-look Celtics, the possibilities intrigue.

We know the post defense won’t be the same*, since Krstic allows better post position than Doc Rivers would like and too frequently seems a step late on rotations. But neither will the offense from the center spot, where Krstic is A) a better shooter than Perkins, B) better at moving without the ball, C) far less prone to turnovers, and D) actually able to catch-and-shoot before an hourglass expires. We expected the rebounding would decrease, but Krstic has quickly become a Serbian Dennis Rodman, and shows no signs of slowing down his suddenly-passable rebounding rate (though my Rodman comparison was certainly hyperbole). We expected Krstic and Green would take a long time to adjust to their new mates, but both seem to have learned their roles quite quickly.

*(In the “weird stat of the day which is probably due to small sample size,” Boston’s starting lineup has performed worse offensively with Krstic than it did with Perkins. And the defense? Wouldn’t you know it, a little better with Krstic than Perkins.)

Green, already, has teamed with the other newcomers (Arroyo et al) to transform Boston’s second unit. Believe me, I spent the first half of the season knowing — just knowing — Boston’s second unit would blow a lead, or kick away a tie game, or turn a small deficit into a considerably larger one. As Boston’s second unit continually blew games or made them far closer than they should have been, I spent far too much time cursing Nate “I love shooting pull-up three-pointers in transition, even though I hardly ever make them” Robinson, wondering why Marquis Daniels produced so little, and hoping Semih Erden would finally start turning his high basketball IQ and solid athleticism into points and rebounds. Now? I no longer expect a second unit blowup, because Green, Arroyo et al have instantly changed the second unit into a functional, capable bunch. My favorite contribution Green has made so far? That I no longer dread when Doc Rivers makes substitutions.

Kendrick Perkins sat in Oklahoma City’s locker room today, calling Pau Gasol soft and Phil Jackson arrogant, making clear for all to hear: the Los Angeles Lakers will not push the Oklahoma City Thunder around, not anymore, not on Perk’s watch. It was the latest sign of the toughness we Celtics fans came to expect from Perk, except now, he makes his claims on behalf of another team.

When the Celtics need that type of toughness this postseason, they’ll have to turn to someone else. Perkins won’t be there to lend an elbow and a scowl. He won’t be there to go toe-to-toe with the league’s biggest players. He won’t be there at all, but Nenad Krstic and Jeff Green will. They won’t provide the same things Perk did, and nobody would ask them to. But they help, in ways Perk couldn’t, in ways that keep the Celtics quite dangerous, in ways that keep the Celtics at (or at least very near) the forefront of any NBA championship discussion.

Perk’s gone, of course. But the Celtics’ new starting five is still undefeated in the playoffs, no?

Doc Rivers believed Kevin Garnett was human, and last night’s 5-19 shooting (yuck) confirmed that suspicion. But Garnett’s shooting will likely return for next game, and the Celtics need not worry about their starting power forward. A more urgent matter illustrated by last night’s loss was Nenad Krstic’s interior defense, which still needs some work.

“He’s got to hold his ground a little bit,” said Doc Rivers.

Criticizing Krstic, after 20 points and nine rebounds, sounds harsh. But Rivers tells the story well. (WEEI)

Rivers would like Krstic to, in coach-speak, “Do his work early. You can see he allows a big to catch it deep and then he tried to defend. With his size, that’s just too late.”

On one occasion, Chris Kaman bullied through Krstic for a two-foot hook shot. On approximately fifteen hundred occasions, DeAndre Jordan worked loose for a dunk. The Celtics bottled up Blake Griffin, almost entirely, but Kaman and Jordan combined for 26 points and 14 rebounds. That said, Rivers believes Krstic’s mistakes are correctable. He’s capable of forcing big men into tougher shots, but — whether because he has never been taught to, or because he doesn’t have the proper defensive focus — does not always succeed in doing so.

Still, Krstic’s early days as a Celtic have elicited far more smiles than frowns. As Ray Allen noted yesterday, Krstic has fit in since day one. He already knows where to find his offense, and his polished skills have given Boston a new wrinkle.

“Krstic, he’s been fine,” said Rivers. “Listen, he’s been better than I knew.”

Teacher and son.

Perhaps the story best illustrates Kevin Garnett as a man, or at least as a teammate. Perhaps it paints a picture of Garnett which has far more clarity than the caricature that has him cussing, throwing elbows, and tapping unsuspecting opponents beneath the belt.

When Kendrick Perkins was traded away, Garnett became emotional, calling it “a tough day” and looking as if someone had run over his dog. The next day, Nenad Krstic and Jeff Green joined the Celtics. Instantly, Garnett became their leader.

“All credit goes to Kevin,” Krstic told CSNNE.com of his fast start. “He’s accepted me from first day. KG has been like a mentor to me; on the court, showing me all the plays. Even on the court, he talks, helps me get in the right position on defense. He has been great to me.”

Just as Garnett was great to Perkins, who once said he scowled so often because it’s tough to smile while trying to win alongside Kevin Garnett. Thinking about the arc of Perk’s career, one wonders how major a role Garnett played in his development. Was Perk always destined to become one of the league’s finest stoppers, or did he quickly become so valuable after teaming with Garnett? It’s difficult to quantify how Garnett aided Perkins, but the advice of a savvy, 14-time All-Star can never hurt. If you place a good sheep with the right shepherd, that sheep shall never stray.

Garnett has a way of taking players under his wing and offering them guidance. If a player listens, Garnett will teach him everything he knows — which, considering that Garnett has become one of the best positional defenders in NBA history, is a very expansive encyclopedia of knowledge. If a player does not listen, Garnett casts him aside as garbage. Garnett, quite literally, will not speak to teammates who lack a thirst for knowledge, to teammates unwilling to improve themselves through simple listening. If a player does not want Garnett’s knowledge, Garnett assumes, that player does not strive for excellence. And thus, he will waste no time or words on that player.

But Krstic and Green do want an infusion of Garnett’s expertise; they want his mentality to permeate into their own skin, as if by osmosis. They want to know what Kevin Garnett knows, which is to say they want a crash course in the finer points of basketball and teamwork, loyalty and selflessness, hard work and winning spirit.

“Kevin, his energy falls on others and I want it to fall on me,” Green told CSNNE.com.

Hardly could Green have spoken a more telling statement. Green now sits in the locker stall next to Garnett, and he knows one of the league’s best resources sits right by his side. The new Celtics have gotten lucky, to be ushered into such a great situation — where a leader wants to lift them upwards, where a team wants only to win a championship, where Doc Rivers needs their help.

In a new city with more pressure and higher expectations, Jeff Green and Nenad Krstic should keep their ears open and their eyes wide. Kevin Garnett’s energy is falling, and they wouldn’t want to miss it.

Nenad Krstic fits in to the Boston Celtics with ease, like he grew up playing alongside Kevin Garnett and catching passes from Rajon Rondo. But Doc Rivers still keeps himself awake at night — quite literally — trying to figure out Jeff Green. (ESPN)

“I haven’t figured out how to use Jeff yet,” Rivers admitted. “I don’t know yet. We gotta figure that out quickly because he’s good.”

He’s good. This we know, even if Green’s advanced metrics point to an average player rather than one deserving of big money this offseason. He’s also quite versatile, which is nice because it allows Rivers the freedom to experiment with different lineups. But Green’s versatility causes Rivers problems which less versatile players don’t:

How should he utilize this new toy? How can Rivers maximize Green’s talents? How can Rivers coax this jack of all trades (but master of none) to help the Boston Celtics win an NBA championship?

Anywhere Rivers puts Green on the court, he should theoretically cause matchup problems. At 6’9, he’s too tall and strong for small forwards — especially backup small forwards, since Green now comes off Boston’s bench. With the speed of a far smaller man and ball skills to match, Green should handle opposing power forwards off the bounce. He should also thrive in transition, where his athleticism should make him a prime target for Rondo’s assists. Even as a small forward or power forward, Green is capable of taking a rebound coast to coast. (That is, if he ever grabs a rebound — sorry, I had to.) He can play with the ball, where his passing vision helps matters, or without it. He can start, he can come off the bench, and he can play the three or four (and Rivers has even experimented with Green and Paul Pierce both playing at the same time, with one of them — I’m not sure which — acting as the shooting guard).

If it sounds like I’m describing someone with All-Star talent, that’s because I am. Green can contribute to a box score in many ways, and, even though he has never produced at All-Star levels, he does have that type of game, somewhere underneath his slightly below-average PER. Which is why Rivers pores over game film, looking for ways to bring the All-Star out of Jeff Green.

“We’re trying to figure out what [all of Boston's new players, including Green] can do well,” Rivers said. “Then we’re trying to put that in our offense and try to run it that way. It’s going to be difficult, it’s going to be tough, but we’re going to get it done.”

Just like Glen Davis did not know his role entering this season, Green now tries to figure out what in the world the Boston Celtics want him to do. Do they want him to score? Facilitate? Defend? Save a cat that’s stuck in a tree? Play three? Play four? All of the above, all at once? Like Davis has, Green needs to embrace his versatility. He can impact games in many ways, so he should. He needs to let the game come naturally and not force things, but use his versatility as a weapon.

Through three games, Green has looked hesitant to play his game. At times, of course, such as his one gorgeous dipsy-doo layup in transition (I believe it was against Phoenix), Green shows why he’s considered a legitimate upgrade to Marquis Daniels. At times he can score (or at least get a shot off) far more effortlessly than most players on Boston’s roster, and far more effortlessly than almost any bench player in the league. He has taken two hard dribbles to the baseline and pulled up for a jumper on at least two separate occasions, and I thought to myself both times, “Damn. He can get a pretty quality shot almost any time he wants.”

There’s also Green’s smaller role. In Oklahoma City, he was the team’s unquestioned third option. In Boston, he doesn’t even start.

“It’s fine, it’s just having that energy right away,” Green said of coming off the bench. “It is tougher when you have been playing 37 minutes, but if I’m playing 16 minutes or 25 minutes, I’m going to give it my all and try to do my best while I’m out there on the court.”

In college, even when Green evolved into a superstar at Georgetown, he was unassuming and perhaps a bit too deferential.Maybe that mentality is partly why he has been hesitant, but the Celtics need Green to become more impactful. They need him to take charge of the second unit, and to play with channeled aggression at all times. They need him to corral his well-rounded talents and become a difference-maker in the mold of a Jason Terry. Not that he plays anything like Terry, because the two are quite obviously very different. But Terry impacts games off the bench like few other NBAers, and Green could reasonably become that type of spark.

The Celtics can win games without Green playing like a weapon. Heck, they’re now 3-0 since Green joined the team, even while he struggles to find his Boston sea legs. But if he ever becomes the player Doc Rivers envisions — the player Rivers searches for while he pores over game film each night — Boston’s bench should finally stop holding the team back, and instead (in a good way) help set the Celtics apart from other contenders.

Athletes Tweets is a Celtics Town feature we used during last offseason. When the news is slow, it can be fun to get a little goofy. Remember, as always, these tweets may or may not be real.

Antoine Walker has lost about 25 pounds, but he has a few more left to lose

@Antoine Walker I love working out with Rick Pitino. He appreciates my quick shots.

@Isiah Thomas Can you believe the Knicks actually tried to hire me again?

@Dustin Johnson When’s the last time you saw the gallery standing in a bunker? SMH.

@Antoine Walker I’m taking my talents to South Beach diet. Lost between 18 and 25 pounds so far. Read more »

Look, I don’t consider myself a fighter and I’ve only thrown a punch on a couple different occasions. But it doesn’t take Mike Tyson in his prime to realize that these guys were swinging their arms like a bunch of sissies. If I’d seen one good punch landed — just one – I might have given this “brawl” the stamp of approval. But not even a thrown chair or a nice tackle near the stands can make me overlook the fact that these guys are throwing “punches” like a kindergarten girl who just got her first cootie shot.

And by the way, that chair throw? That was the weakest part of this whole fracas. Nenad Krstic needs to do himself a favor and go back and watch some tape of Bob Knight and take notes. The next time Krstic throws a chair, I expect it to have a little more oomph behind it.

Anyway, I probably wouldn’t have even blogged about this so-called fight if it weren’t for this picture:

Simply terrific. There’s some random car in the background and that camera man on the right doesn’t have a single care in the world.