They've said things like "It will come together" and "We are better than this" during what is now a 14-16 stretch. Coach Doc Rivers is fond of the old "I love this team" when pressed on what needs to change.
Yet for all their efforts to verbally defend one another, their defense on the floor of late has been, well, indefensible.
After Saturday's 104-96 loss to the offensively inept New Jersey Nets, a result that gave the Nets just their sixth win all season, the Celtics had established a new low.
For the first time in the new "Big Three" era they have allowed four straight opponents to score at least 100 points. The last time it happened was in April 2007, a stretch during which Rivers was starting guys like Gerald Green and Allan Ray at the end of a 24-58 season.
Right now, less than two years removed from a championship and with a team designed to shut down opponents, it's a bit more of a concern.
"You get a team that's desperate and has a chance to win and beat us… they came to life" Rivers said of the Nets, who had lost 12 straight in the series. "They made a lot of shots. But we just gave up 104 points again…That's on us. It's on us. And one of the things we told [the team], we told them yesterday, 'It ain't the system. It's our heads. It's between the ears. And we've got to come out and play. Everyone wants to beat you, you can bank on that.'"
New Jersey entered averaging a league-low 90.1 points, giving it a realistic chance of becoming the first NBA team since Portland in 2005-06 to average fewer than 90.0 for a season. It had topped 100 just seven times prior to the trip to the Garden.
Boston, meanwhile, still leads the league in scoring defense, but this recent stretch of futility suggests to the C's that they are nowhere near the best defensive team in the NBA.
"We're a team that takes a lot of pride in getting stops," said Kevin Garnett, who had 26 points and nine rebounds. "We have to get back to that."
They seemed to early on Saturday, racing to a 12-2 lead and forcing the Nets to miss their first five shots. New Jersey, which entered with a league-worst 42.6 percent mark from the field, made 48.5 percent thereafter and never trailed after a Keyon Dooling jumper to end the quarter.
New Jersey's lead built to a shocking 18 points before Boston rallied, but the Nets had already built an expressway to the foul line that carried them to the finish.
In the end, they took 30 more free throws than the Celtics, getting an extra 23 points from the stripe. Many of the fouls came on desperate swipes by beaten Boston players, a sure sign that the defense had rested.
Rivers said his players got what they deserved.
"I thought our guys gave a great effort in the second half, but then they started making shots, and then we'd have the defensive breakdown with three seconds on the shot clock over and over again," he said.
"Every time we got it down to six or four a guy would make a three, a bobbled ball would go to [the Nets]. I talk about it a lot with our guys: 'Those are the basketball gods punishing you; you have no right to get back in this game.'"
With 25 games still to come, Boston has already eclipsed last season's total of 20 losses. It was weeks ago that they surpassed their quota for defensive answers to difficult questions.
"Hearing it is starting to make ears ring," Garnett said.