Even before the Celtics went into a prolonged funk, Doc Rivers had his doubts about the way his team was playing.

“We like our record, but we’re not building,” the coach said then. “We’re winning games, but we’re not improving.”

Then the Celtics started losing games and the questions began tumbling out about whether this team — the same one that blew away the competition in November and had people seriously suggesting it could win 70 games — was a legitimate contender. The answer lies somewhere in between those long-forgotten boasts and the C's current state, which is, to put it charitably, inconsistent.

Injuries have been the primary concern, as they should have been when blind optimism was running wild before Thanksgiving.

The members of the starting five have sat out 19 games between them, with Kevin Garnett’s 11-game sabbatical leading that number. Glen Davis missed 28 games and Marquis Daniels has been out 23 and counting. Paul Pierce had knee surgery, Rasheed Wallace missed time with a foot injury and Tony Allen had an ankle injury.

No one knows for sure how long the Celtics will be able to stay in one piece, and any questions about their long-term standing have to be viewed through that prism. But beyond the injuries, the Celtics 'play the last few weeks has revealed cracks in the foundation that didn’t seem so apparent before the new year dawned.

These are things that need to be addressed in the second half of the season, and Garnett’s return alone can not solve all of them.

IS THIS IT FOR RAY ALLEN?

The first salvo in what will surely be an eventful trade-deadline season was fired when a report surfaced that the Golden State Warriors would like to take Allen off the Celtics' hands for a package including Monta Ellis.

As with so many rumors that will arise between now and the trade deadline, there is something to it, but not much. Of course Golden State would like to blow up its team and get rid of onerous deals in exchange for Allen’s expiring contract, but if you’re looking for the Celtics to make a big deal involving Allen, you’re probably going to be left waiting.

We’ve been down this road many times with Allen before. He was left for dead after the first two rounds of the Eastern Conference playoffs in 2008, and then rebounded with an inspirational showing against the Lakers in the NBA Finals.

People wondered if he was done early last season, and he turned in one of the finest shooting seasons of his career. After torching the Bulls in the first round of the playoffs he struggled against the Magic and the questions returned.

It’s understandable that people would be waiting for the other sneaker to drop in regards to Allen given his age, but he’s been defying time for years, and it’s way too early to give up on him now. Yes, his shooting percentages are not at their lofty heights of a season ago, but look closer and you’ll see that Allen is turning in a remarkably similar campaign to his first one in a Celtics uniform, with one glaring exception: his 3-point shooting.

Allen is shooting below 35 percent on 3’s for the first time in his career. The last time he even came close to the 35 percent mark was in the lockout-shortened 1998-99 season, when everyone’s numbers took a hit.

He remains completely, almost catatonically, confident in his ability to shoot. Witness his dreadful performance against Portland and his unhurried clutch 3-pointer in the final minute that turned the tide.

Somewhat remarkably, Allen and Kendrick Perkins are the only Celtics regulars who have played in every game this season, and at better than 36 minutes a night Allen is the team leader in minutes played.

If you’re going to replace Allen you have to replace not only his shooting and his stamina, but also his ability to blend with his teammates and produce the best lineups the Celtics have to offer. It’s a phenomenon that has been documented previously, but Allen is present in the most productive combinations available to Rivers.

Whether Allen remains a member of the Celtics beyond this season is very much an open question, but while you never say never in this league, it would be shocking if Allen was dealt before that time comes.

SO, WILL THERE BE A MOVE?

Probably. It’s dangerous to underestimate Danny Ainge’s ability to get creative, and in the last few seasons he has turned to some unlikely sources for help.

Ainge’s best deadline move was coaxing P.J. Brown out of retirement, but he also was able to wait out the Clippers in getting Sam Cassell, the Knicks in acquiring Stephon Marbury and the Kings in obtaining Mikki Moore.

Compared to Brown’s invaluable contributions, Cassell, Marbury and Moore were luxury items, but all four were acquired through untraditional means and at no cost to the Celtics other than money.

Ainge has assets to deal, namely the expiring contracts of Ray Allen, Brian Scalabrine, Tony Allen, Eddie House and J.R. Giddens. He also has a first-round pick if he’s inclined to move it. More importantly, he has an open roster spot after waiving Lester Hudson.

Watch the waiver wire closely as the deadline approaches. Teams may be willing to pursue buyouts to save a few dollars, and that’s where the Celtics may strike.

Ainge’s interest in Allen Iverson and his reported pursuit of Nate Robinson may have tipped his hand in terms of a direction. The bench has several needs — ball-handling and rebounding among them, but it specifically needs another scorer who can create his own shot.

Like Ray Allen, Eddie House has struggled with his shooting this season. Those instant bursts of offense that are his trademark have been nowhere to be found. Another scorer would help take the pressure off the second unit, as well as Pierce and Ray Allen.
“I like our team,” Rivers said. “I’m willing to go into the playoffs exactly the way we are right now.”

That’s exactly what you would expect the coach to say, and the early season results indicated that this team may be good enough without the benefit of a move, but history has shown otherwise.

WHO WILL BE IN THE ROTATION?

Rivers likes to use a nine-man rotation, and if everyone is healthy, House, Daniels, Wallace and Glen Davis would seem to be the viable four reserves. But that unit has not played a single minute together all season thanks to the injuries to Davis and Daniels.

While Davis was out, Shelden Williams stepped in and provided strong rebounding numbers, but he has since been passed over not only by Davis, but also Brian Scalabrine and even Bill Walker.

“He’s working hard right now,” Rivers said. “He’s just got guys in front of him. We knew that when we signed him.”

For his part, Davis has not yet hit his stride. In limited minutes he has been the team’s best and most active offensive rebounder, but his shooting has been sub-par and he did little to answer questions about his maturity with his ill-timed confrontation with a fan in Detroit.

In the absence of Daniels, Tony Allen has played an unlikely supporting role and it remains to be seen if he will continue to get time when Daniels returns around the All-Star break.

For all his shortcomings, and for all the angst he causes for Celtics fans, Tony Allen remains an intriguing enigma. He is stronger and more athletic than Daniels and he could, at least in theory, provide sporadic bursts of inspired man defense against hot perimeter players.

The key to all this remains Wallace, who has been a welcome addition to the locker room and an important figure in terms of depth. But Wallace’s play has not lived up to his advanced billing, and the Celtics will need more from him in the second half of the season.

IS THIS RAJON RONDO’S TIME?

It better be.

The All-Star teams will be announced on Thursday, and if there’s any justice in the world, Rondo will be a member of the Eastern Conference team. With that honor and a five-year extension in his pocket, Rondo will have checked two notable goals off his to-do list for the season.

Now all he has to do is lead the Celtics back to the championship.

Make no mistake, the Celtics still are Pierce’s team and Garnett is the player around whom the entire thing revolves. But Rondo is on the cusp of grabbing the reins, and once he does, he won’t let go.

“Pretty soon he’s going to here, the face of the franchise when we’re all gone and in our rocking chairs,” Pierce said last week. “He’s doing a great job. He’s maturing this year. It’s fun watching him grow and become a complete player.”

There has been a complete change in the quotes and observations about Rondo from his teammates and coach this season. Gone are the admonishments, subtle and otherwise, about his play and his mental approach. They have been replaced by a tacit understanding that he has moved beyond the on-the-job training phase of his career and the acknowledgment that he is now a full-fledged member of the inner circle.

Rivers, who has been known to ride his point guard relentlessly, has in public been quick to back him up and lay blame elsewhere. The Celtics have come to the realization that they can’t win in spite of him anymore and that they need him as much as he needed them.

The next step for Rondo is to be a brilliant playmaker all the time and not just most of the time.

Before the game with the Clippers, Rondo sat by himself watching video of Baron Davis, who had tormented him in their previous meeting in Los Angeles. Various coaches came by and gave him suggestions, but Rondo’s mannerisms, as always, suggested that he had full confidence in his ability to handle the task at hand. And he did, keeping Davis out of the paint and forcing him into a 5-for-14 shooting night.

On the other end of the floor Rondo was at his best, racking up 12 assists and 16 timely points along with seven rebounds and four steals.

He has for some time been the best point guard in the Eastern Conference. Now he has to be that player every night.

DOES THIS TEAM REMIND YOU OF ANOTHER?

Yes, and it’s not necessarily a compliment. In terms of temperament, experience and even approach, the Celtics bear an uncanny resemblance to the Detroit Pistons, circa 2005-08.

Like those Pistons teams, the Celtics have a championship in their back pocket. Like those Pistons teams, the Celtics believe they have uncovered the secret to winning games with their defense. And like those Pistons teams, the Celtics sometimes believe they can summon those qualities at will.

It’s a dangerous trap, and the Celtics have fallen victim to it several times already this season. Most recently in the second half against Detroit and even at home with losses to Atlanta and Dallas. Rivers said as much last week during his weekly call with Dennis & Callahan.

“I think at times it’s not a chemistry problem, it’s more a focus problem. I said that earlier in the year and I identified that two weeks into the season, it will never be X’s and O’s with this team. It will never be basketball IQ. It will be being bored with the process. That happens right now.”

Garnett summed the whole thing up, as well, after practice last week.

“Our defense is built off of trust. It isn’t necessarily an assignment, but it is a type of defense in which we hold each other accountable. Whatever the defense calls for, for one person to do his job, the natural reaction is for his teammate to be there to help him and then so on and so on.”

That’s not something you can just decide to do one night and leave behind the next. The lulls will happen, whether they are because of injuries, the schedule or just the winter doldrums. But the Celtics always have been able to snap out of them before they became full-blown issues by focusing on their defense and taking care of all the little things.

This team has not shown the ability to do that yet, and if it can’t, it won’t be a banner spring in Boston.