When he was coaching the New England Patriots, Bill Parcells uttered what has become a famous maxim in sports: "You are what your record says you are."

After the Boston Celtics dropped to 15-15 thanks to a horrific collapse in the Big Easy on Sunday afternoon, losing 120-115 to the New Orleans Pelicans after leading by as many as 24 points in the second half, it certainly applies to them.

"We've got a lot of things to clean up, obviously," Celtics coach Brad Stevens said.

Sunday's debacle was a microcosm of Boston's whole season. The Celtics got moments of brilliance from Jayson Tatum and Jaylen Brown, who even on off days for them overall still combined to score 57 points. Meanwhile, they didn't get much from everyone else, as the rest of the team managed only 58 points while shooting 4-for-20 from 3-point range.

Eleven of those misses came from Kemba Walker, whose up-and-down (though mostly down) play since debuting in early January after completing a 12-week strengthening program for his troublesome left knee has been as constant as Boston's continued hovering around .500. After Walker had his best game of the season Friday night in a win over the Atlanta Hawks, scoring 28 points and going 10-for-16 from the field -- the fourth time this season Walker hit at least half his shots -- Stevens gently chided his point guard's critics, and Tatum said the All-Star guard's play is beginning to come around.

Walker followed that up by going 5-for-21 in a season-high 36 minutes Sunday, including a 1-for-12 mark from 3-point range. He's now shooting 37.1% for the season, and the Celtics are being outscored with him on the floor.

Overall, the Celtics look like a team that never replaced Gordon Hayward, who has played at an All-Star level after signing with the Charlotte Hornets in the offseason. Obviously the recent loss of Marcus Smart to a calf strain -- an injury that has kept Smart out of the lineup since Jan. 30, and one that ESPN's Adrian Wojnarowski reported before Sunday's game will keep Smart out until after next month's All-Star break -- is part of Boston's troubles. But the Celtics also did nothing to replace Hayward's production on the wing in the offseason. Instead, they signed another point guard (Jeff Teague) and another center (Tristan Thompson) on a roster heavy on players at both positions.

Teague has been an abject disaster, shooting under 30% on 2-point shots this season and deservedly being banished from Stevens' rotation in favor of rookie Payton Pritchard. Thompson, meanwhile, has slowly worked his way back into form after a hamstring strain cost him all of training camp with his new team. But even his improved play has left Stevens juggling a rotation that he admitted before Sunday's game is imbalanced thanks to three of Boston's better players -- Thompson, Daniel Theis and Robert Williams -- all being centers.

"I've said this all year: One of the challenges of our team is that you get past our best perimeter players, and the next probably three best guys as far as production goes so far on our team are, at first blush, 5s," Stevens said.

As Stevens continues to search for wing production, the team's other rookie, Aaron Nesmith, has been the first player off the bench the past five games. And while he's been fine, he isn't anything close to an approximation of what Hayward was for Boston last year -- let alone what he's been for Charlotte this season.

That has left a heavy burden on Tatum and Brown to produce for the Celtics. And in games like Sunday afternoon, when Walker was struggling to hit from the perimeter, that allowed New Orleans to throw everything at the two of them without worrying about anyone else on the court -- a formula that allowed the Pelicans to claw their way back from a massive deficit and, eventually, win in overtime.

"Obviously we gave ourselves a chance in overtime," Tatum said. "But if we want to be a really good team, we've got to put teams away earlier, especially being up 20-something points.

"But we let them come back."

While Stevens hasn't ever quite said it the way Parcells once did, he hasn't been shy to point out that, as Boston has hovered around .500 for the past few weeks, there's little reason to believe the team's current form should allow it to be better than that. Yes, Boston hasn't had Smart, but virtually every team has dealt with significant absences due to either injury or the NBA's health and safety protocols regarding the ongoing COVID-19 pandemic.

The combination of those ongoing struggles, along with the team's president of basketball operations, Danny Ainge, declaring, "Our roster obviously is not good ... there's no ifs, ands or buts about it" in a radio interview this week, will place a bright spotlight on Boston between now and next month's trade deadline.

From the time Boston wakes up Monday morning, it will be 31 days until the March 25 deadline -- a stretch in which the Celtics, armed with all of their first-round draft picks going forward and a massive trade exception from Hayward's departure during the offseason, will be expected to make a move to supplement their current roster.

If they can make a move, they'll have an opportunity to make a run in an Eastern Conference that features several potential contenders -- Boston included -- that all have severe flaws. If they can't, it's hard to see how they will.

After all, we're 30 games into a 72-game season, and the Celtics are a .500 team. And, in this case, their record says exactly what they are.