From the beginning, the Celtics were built around the idea that their three veteran All-Stars -- Paul Pierce, Ray Allen and Kevin Garnett – would be the foundation for everything they did. Rajon Rondo has since been added to that group, which shifted the equation only a little. Pieces would be added that complimented their games, but at the end of the day their fortunes are tied to their play.

When team president Danny Ainge made the trades that turned over a third of the roster he did so with the knowledge that his core group would remain intact and that players such as Jeff Green and Nenad Krstic in particular would be able to play off the All-Stars’ strengths.

For all the changes the team had made, the Celtics’ fortunes in the postseason will rise and fall on their shoulders and now that the team is struggling through its most inconsistent stretch of the season, Doc Rivers said the responsibility to lead is on their shoulders.

“I’m not blaming anybody. I always blame me myself. I don’t ever blame,” Rivers said. “It is their responsibility, always. It always starts with their best players and everybody else follows. That’s how we constructed this team. On purpose. It was the big three and now Rondo’s been added to this group and they all have that responsibility.”

That responsibility takes many forms and part of what makes them so unique is they all go about it in different ways. But the thread that holds the whole enterprise together is their willingness to talk with each other.

“Communication is big,” Allen said. “On the flipside of it, on bad teams, you come to the locker room and you’re mad at everybody. You look at the guy next to you and say, he’s doing this, he’s doing that, he’s pissing me off and you get mad at the coaching staff. That’s when the dissension starts. On our team, you come in and you just have a conversation. You might not even talk about the game. You just remember to stay brothers and communicate.”

Still, there’s talking about it and there’s getting it done and the Celtics know they can talk about what has gone wrong all day and night but until they tighten up on the floor nothing will change.

“I believe between the four of us, we have to play better,” Allen said. “Whether it’s not making a shot down the stretch or getting a defensive stop, between the four of us we have to do better. We have to set the example, be the example and always show it.”

There are a number of different areas that need improvement, but the two biggest areas are the start of the game and the end. Those are the starter’s minutes and while the Celtics got off to a better start against the Bobcats on Friday, they folded down the stretch in blowing an 11-point lead.

“It’s a roller coaster right now,” Rondo said. “Some games we have it and some games we don’t. There’s no consistency in our play in the fourth quarter.”

Rivers believes that the problems the team is having right now are all mental. That’s part of the reason why he was so frustrated with their play this week. Even in games that they won – against New Orleans and New York – the Celtics were badly outplayed for entire halves in each of those games. Counting their blowout loss in Houston, that’s five straight games of inconsistent play.

With all due respect to Green, Krstic, Glen Davis and Delonte West, they can’t solve the Celtics problems. It has to come from the big four and with the exception of Garnett, they all have issues.

Rondo’s struggles have been well-documented. In his last eight games he’s made only 21-of-72 shots and attempted just eight free throws. His injured pinky finger is definitely bothering him. “Every time I touch it really, it hurts,” he said.

Pierce has also been inconsistent, converting on just 28 percent of his 3-point attempts during that stretch and shooting just 42 percent from the floor. It’s been the same for Allen who has mixed great games with nonexistent ones offensively. Of the four, only Garnett has maintained a consistent level of production.

That’s the crux of the Celtics problems right now. For all the hand-wringing over the trade deadline shake-up, the Celtics defense has remained constant. It’s been their offense that has gone south and they’ve been performing at Cleveland Cavalier levels of efficiency. They have shot over 50 percent as a team just once in the last 10 games and have missed an astonishing 81 of their last 113 3-point attempts.

“Bad starts, bad finishes equals losses,” Rondo said. “That’s what we’ve been getting lately.”

The good news for the Celtics is that the talent is still there. While Rondo is definitely banged up, Garnett, Pierce and Allen are all relatively healthy. That’s a dramatic change from last season and if you’re looking for something optimistic, that’s a good place to start. They have what it takes. That’s been proven time and again. Now they just have to get it done.

Asked what it will take to move on, Rondo had a simple reply: “You win.”