Can Celtics surge like last season?

After spending four years crafting a reputation as one of the NBA’s best teams in November and December, the Boston Celtics have found the last two seasons to be rather unkind when it comes to getting out of the blocks quickly, with early hardship coming to define them in their old age.

It started last year when, without a training camp to rely on, coach Doc Rivers’ past-its-prime roster took a 15-17 mark into the All-Star break during the condensed, lockout-shortened season. Boston was essentially left for dead as a result, written off as finally too decrepit to hang with the league’s young, up-and-coming powers — especially at the headlong pace the league had them playing.

But then the Celtics shocked virtually everyone in the second half by winning 24 of their final 34 games, becoming just the fourth team in league history to win its division after having a losing record at the break. That Boston team earned the No. 4 seed in the Eastern Conference as a result and then continued to defy all logic by coming within one win of its third NBA Finals appearance in five seasons.

With their 2011-12 volte-face in mind, this season’s Celtics entered Tuesday’s Christmas Day matinee against Brooklyn hopeful for the future despite their 13-13 record and an uncomfortably familiar view from the fringe of the Eastern Conference playoff race with a third of the season in the books. And a 93-76 win over the free-falling Nets helped Boston keep its head above water and maintain its No. 8 seed in the East.

But there are still serious questions as to whether another U-turn like last year’s is feasible with this season’s retooled lineup, even with an extra 16 games to make it. And regardless of what you think you saw Tuesday, these Celtics, as currently constructed, don’t have another stunning turnaround in them.

“I think we’re getting better,” Rivers said of his club, which, at 14-13, is one win off its 2012 pace heading into Thursday’s game against the LA Clippers. “I think we’re very, very close to becoming a good team, but we’re not yet. Our record tells us we’re not. So until our record tells us we are, we’re not.”

There are a number of reasons Rivers won’t say his team is good and fans don’t think Boston is capable of a run like the one it put together last year. Chief among them is the fact that last year’s “bad” start really wasn’t all that bad, while this year’s has been every bit as bad as it looks.

Sure, things looked ugly last winter when Celtics GM Danny Ainge publicly considered razing his roster and starting from scratch with his team hovering around .500. But the thing that stood out about Boston’s subsequent recovery after Ainge’s flirtation with an overhaul wasn’t how rapidly the season changed course, but how little Boston actually changed on the floor as it did.

Most will point to the Celtics’ stalwart defense as the reason for their success last season. But, statistically, the D that went 15-17 in the first half of the season was virtually identical to the one that dominated the league in March and April, even after Kevin Garnett’s successful, if uncomfortable shift to center and Avery Bradley’s emergence as a reliable on-ball defender starting in place of Ray Allen.

Boston held opponents to NBA lows in shooting (41.9 percent) and 3-point shooting (30.8 percent) last season, but it wasn’t the result of a post-All-Star lockdown — the Celtics were second and first in those marks, respectively, before the break, as well. Over its first 32 games, Boston allowed 88.5 points per game on 41.8-percent shooting, and over the final 34, it allowed 90.1 points on 42-percent shooting.

Last season’s Celtics offense, while unremarkable, was also mostly consistent, too. Though Boston averaged nearly five more points during the second half of the season, its second-half shooting percentage went up only one point from January and February, while the Celtics saw a 2.5-percent decline in 3-point shooting.

The only place Boston really showed a marked improvement after the break last year was in the turnover game — but not necessarily by taking better care of the ball. Before the All-Star Game, the Celtics averaged 14.7 turnovers while creating 13.6. In the second half, the Celtics turned the ball over 13.5 times per night while generating 15.7 on defense.

In short, last season’s Celtics team was always good, and it just took half a season — and one Ainge threat of a scorched-earth roster transformation — for the wins to line up accordingly. The 15-17 start was a fluke.

This season, however, it’s a case of new problems, not bad luck, leading to the same bad results. And this season’s issues — a core that’s another year older and an overhauled roster that’s struggling to gel like the Celtics teams of yore — may be tougher to solve in time to make a run.

In a paradigm shift from the Boston teams that have dominated the East since the birth of the Big Three, which is down a member with Allen playing in Miami, these Celtics are making their name on offense, if anywhere, shooting a top-five 46.8 percent from the floor and scoring 97.3 points per game.

But Boston also entered Tuesday 18th in the league in opponent shooting percentage, at 45 percent, and 16th in defending the 3, giving up 35.8 percent from behind the arc.

Garnett, 36, is continuing to play well, though not quite at the level of last year’s playoff run, when he averaged 19.2 points and 10.3 rebounds. Paul Pierce is still the team’s scoring leader, not to mention its emotional leader in the huddle, even at age 35. And Rajon Rondo is still the same enigmatic, temperamental wizard with the basketball that he always was, leading the NBA in assists by a wide margin.

But the rest of the roster is still searching for a purpose, and the bench has been a veritable mess. There’s no telling whether there will be another Bradley to step up from the ranks of the reserves this season, though Bradley’s imminent return from shoulder surgery will help, and rookie big man Jared Sullinger (16 points, 6-of-7 shooting) and forward Jeff Green (15 points, 5 of 8) provided a glimmer of hope on Tuesday.

If there was anything to be gleaned from last year’s second-half surge, it’s that the Celtics should never be counted out, even when you’re positive that their time in the spotlight has run its course.

But whereas last season’s team was able to rebound from a bad start by continuing to do what it was already doing, this season’s needs to make some huge strides, particularly on defense, if it wants to become competitive in the East again — and I’m not as optimistic that it can happen as Rivers is.

“I hope so, I do,” Rivers said when asked if this team can rally like last season’s. “But . . . you’ve heard (Heat guard Dwyane) Wade talking about how they’re not there yet, you heard (Thunder forward Kevin) Durant saying that, and I’m thinking, ‘What else do they have to do?’ (Lakers guard) Kobe (Bryant) said that, that they’re not there yet, too.

“So there’s a lot of teams saying the same thing. Somebody is going to do what they say and take off, and I’m hoping that it’s us.”

You can follow Sam Gardner on Twitter or e-mail him at samgardnerfox@gmail.com.