What's going on with the Celtics, and can they bounce back before the playoffs?

BOSTON -- There was a time not so long ago when the Celtics were the best team in the NBA, possessing a lethal and high-powered offense that very few teams could contain. Their historic offense saw Boston surge to a 21-5 start to the season, putting the green as the odds-on favorites to win it all come summertime.

But for a while now, the living hasn't been so easy. The Celtics have been mere mortals since early December and, dare we say, a middling to bottom of the barrel team since the All-Star break.

Bottom of the barrel is maybe a tad bit harsh. Since that 21-5 start, the Celtics are just 24-16, which isn't terrible by any stretch. But they set the bar so high in October and November that their recent dip in play is well below what we know they're capable of reaching. The threes are not falling as gracefully as they once were on offense, and the unit has been middle-of-the-pack with a 114.3 rating since Dec. 10, ranking 17th in the NBA. All that talk of this team joining the history books has become, well, history.

The defense has improved with a 111.5 rating -- good for fourth in the NBA -- over that stretch, and that is promising. It was their defense that catapulted last year's Celtics to the NBA Finals, and that intensity has been severely lacking throughout most of this season.

But their offensive deficiencies have cost them games as of late. They've lost their identity on that side of the ball, outside of a team that jacks up a bunch of threes. And the issues have only been even worse since the All-Star break, with the C's going just 3-4 since Jayson Tatum and Jaylen Brown stole the show for their respective teams in Utah. 

The Celtics came back from the break and had to fight for wins over the Pacers and 76ers, before getting punked once again by the New York Knicks. After a win over the Cavaliers -- their only victory over Cleveland this season -- they've since gone out and blown double digit leads to the Nets, Knicks, and Cavs in the span of four days.

We're beginning to see a mirror image of last season, when Boston got off to a fairly pitiful start before going scorched earth after the new year. They learned that sharing is caring on offense while also taking things up to another level on defense. They rode that all the way to the NBA Finals, and then used their title loss as jet fuel to fly past the rest of the league in the early goings of this season.

Now, the Celtics find themselves trying to find themselves with 16 games left before the playoffs. Players are talking about rediscovering their swagger and getting back the groove that had the team off to its torrid start. The Celtics have just over a month to reclaim their mojo.

"We should be fighting to win," Brown told reporters after an overtime loss in Cleveland on Monday. "That's what it should be. Whether you're in a rhythm or not in a rhythm, what matters is winning games. At this point in the season, I think that we are fighting to get in our own rhythms a little bit too much, and that's from the top to the bottom. We should be fighting to win."

The problem has been that the fight hasn't just been there are times. The Celtics have always relied on the three-ball, but at least they used to generate good and open looks for each other by driving to the hoop first. Lately, the Celtics have been allergic to the paint, settling for contested looks early in the shot clock far too often.

And they aren't hitting those looks, either. Tatum is hitting only 28.8 percent of his threes in his six games since the break. The team is taking slightly over 40 threes per game in the seven games back from the break, and hitting just 37 percent of them. When a team misses that much, they better have eyes for any and all offensive rebounds they can get their hands on. That part takes effort though, and the Celtics have been coming up short in that department too.

Maybe the Celtics are just in cruise control, pacing themselves for what they hope is a long summer ahead. But the mental errors and poor shot selections that have plagued their recent losses paint a troubling picture, especially since they've been against teams the Celtics could eventually see when the playoffs tip off.

"We've had possessions that have been pivotal and we haven't executed. Rebounds, loose balls, turnovers, free throws. All of that stuff -- me included," Brown said Monday. "As we move forward, if we want to do what we want to do, this is the time where you improve, this is the time where you respond. I look at it as a glass half full rather than half empty. It's a part of the journey. You've just gotta respond."

Head coach Joe Mazzulla has had to evolve since shedding the interim tag last month, and we're not just talking about him kicking his feverous gum habit. He's started to call timeouts, whether to stop an opposing run or draw up plays late in a game. He's trying to deliver some tough love too, as he did when Grant Williams logged a DNP-CD last week. (Grant may be in line for another after Monday night's mini-meltdown at the free throw line.)

But right now, Mazzulla wants his team to focus on what they're great at and return to what put them ahead of the pack earlier this season. He's hoping this bumpy road is an important stepping stone in the process, a reminder that the team needs focus and get to work each and every night.

"If it gets worse, it needs to get worse for whatever reason," he said Monday. "I don't look to anything except what do we need to do every day to get to where we need to get to. Everything we're experiencing from a basketball standpoint is for a reason and as long as we learn from it and grow -- we haven't learned about late-game offensive rebounding yet, and so, this might be the fifth or sixth loss, and so that part pisses me off. Other than that, it's just part of it."

Unfortunately, these are the kinds of things you assumed the team had a handle on after making a run to the Finals last season. They shouldn't need reminders like their embarrassing collapse against the Nets or overtime losses to the Knicks and the Cavs.

The Celtics are still a talented team with two studs at the top, important players like Smart, Al Horford, and Robert Williams (when healthy) doing their part, and one of the deepest benches in the NBA. They should be able to fix what has been leading to some regrettable and frustrating evenings over the last several weeks.

But they have to want it in order to get back on track. That's something they shouldn't have to be reminded of, especially this late into a season.