Yes, it's time to worry, folks

BOSTON -- Sure it's only January, but feel free to be officially concerned about where these Boston Celtics are headed.

Their coach is. After watching his team roll over to a flawed Dallas Mavericks team at the TD Garden on Wednesday to drop to a game under .500, Doc Rivers plainly spelled out the Celtics' disturbing deficiencies.

There were subtle, less-tangible issues, among them a malaise that permeated the lineup (with the pointed exception of Rajon Rondo and Michael Pietrus in a spirited Celtics debut) and a lack of trust on defensive rotations.

Then there was the "just the facts" problems, which included an outrageous 17-0 deficit on second-chance points in addition to a lopsided 20-9 disparity on points off turnovers. You know, "energy baskets."

"So that's 37 points before you start the game, against the team that won the title last year," Rivers said. "It's very difficult."

Bostonians have been down this road before. It was excruciating to watch Larry Bird and Kevin McHale break down physically as the cohesiveness that once made them champions unraveled. Amidst the crumbling of that dynasty, Robert Parish played the role of Ray Allen, the ageless wonder who went on to win another title in a different uniform.

This collection of Celtics veterans claim their time has not passed. It is, explained Allen, a matter of rejiggering their chemistry.

"There's no concern that we can't turn it around,'' he insisted. "We've been here before."

In the meantime, Rondo continues to assault opponents as though they were to blame for the trade rumors that tainted his preseason. While the point guard's teammates slogged through another listless performance, he was electric with 24 points (including 8 free throws), 7 assists and 3 steals in 38 minutes.

By comparison, the rest of the starting lineup combined for 34 points on 10-of-27 shooting.

This is Rondo's team now. He is driving a new Maserati while his cohorts are chugging along behind in a beat-up jalopy. There's evidence to suggest this is a permanent trend, not a temporary solution while his elders find a way to get up to speed.

All I know is these Celtics used to win these games. There were countless occasions when they banged around for three quarters, then got serious and
closed the deal on their own floor in the final frame.

After Pietrus stripped the ball away and sent Rondo flying on a fast-break layup to tie the game 77-77 with 6:04 left in the game, the Garden erupted, Dallas whistled for timeout and an exhausted Pietrus, who didn't even cross half court once Rondo took off, signaled to Doc that he was done. He had played nearly 18 minutes.

No worries. Pietrus was replaced by Paul Pierce, who logged an extended rest while Pietrus, the Celtics newcomer, exhibited the kind of hustle and energy that Rivers has been publicly calling for the past week.

Aside from a monster 3-pointer that tied the game 85-85 with less than 30 seconds to go, the captain was, for the most part, ineffective. Pierce had his first real practice just two days ago, so there's hope as he rounds himself into basketball shape in the wake of a cranky Achilles' that some of Boston's offensive woes will dissipate.

That's what it has come down to after less than a month of this lockout-pocked season: Hoping Pierce rediscovers his mojo in time to salvage his team's psyche.

Until he does, Boston doesn't have enough answers when talented players such as Dirk Nowitzki deliver for their team with the game on the line, like he did Wednesday night.

It's not that Dallas looked championship driven, either. They, too, have issues.

In fact, there were moments when the first half could have easily been mistaken for one of those NBA old-timers games that finally (and mercifully) were eliminated because the aging superstars kept blowing out their knees.

No knees were harmed in the making of Wednesday night's debacle, but there were enough aging superstars in the building to film a Miller Lite commercial.

Remember when Vince Carter used to elevate, when they called him In-Vince-able because, well, no one could really stop him? That was about five years and three teams ago. Each time Carter tried to go airborne against the Celtics, there was nothing else to do but cringe. No lift, no chance. Carter and his Shaq beard finished 1-of-8 from the floor.

Remember when Kevin Garnett used to haul in an offensive rebound in traffic inches from the hoop, then stuff home a rim-rattling dunk with a primal scream to match his fury? In this game, when KG grabbed that same rebound under the basket, he dribbled out to the baseline and took an 8-foot fallaway that bounced short.

Again, what else to do but cringe?

There has been legitimate hand-wringing over KG's underwhelming start. He is not unlike former Red Sox ace Pedro Martinez in his later years. Petey used to live and die by the heat of his fastball; in the stretch run of his brilliant career, he learned to be wily and clever and deliver offspeed pitches.

KG's offspeed pitch ain't bad. It's that shot from the elbow that his former Minnesota Timberwolves coach, Flip Saunders, swore Garnett hit at a 70 percent clip in his heyday. It remains a lethal bullet in KG's arsenal, but only if he's willing to shoot it.

There are few players prouder than KG. And Garnett, while not as explosive as he used to be, still plays hard, still lives to defend, and gives you a full honest night of sweat. His numbers were respectable against Dallas (16 points, 10 rebounds), but one of the lasting images of this damaging loss was an awkward, wide-open, short-armed attempt by KG in the final minute of the game that clanged off the rim.

Blame the lockout, poor conditioning, or two rosters that calcified overnight. All of those excuses have merit. None of them make for good basketball.

The difference is the Mavericks came into a formerly hostile Garden and won ugly.

The Celtics simply found another way to lose.

Longtime Boston journalist Jackie MacMullan is a columnist for ESPNBoston.com.