With NFL free agency is full swing, you’re seeing teams trying to upgrade on both sides of the ball. The New England Patriots traded for Brandin Cooks to improve their receiving core and added one of the top free-agent corners in Stephon Gilmore. In football, you don’t have to worry about guys playing offense and defense. That’s what makes basketball so difficult on the personnel level.

Somebody might be a great shooter, but that’s negated if he’s a revolving door on D. A rim protector sounds great, but can he stretch the floor and pass on offense? It’s a careful balance that GMs and coaches strive to strike when they’re looking to fill out their roster. Heading into the All-Star break and the trade deadline, the Celtics were a very good offensive team (6th in offensive efficiency at 109.6) and a below-average defensive team (18th in defensive efficiency at 106.2).

At 37-20, Danny Ainge opted to not make a move and let it ride and since then, the team has gone from Jekyll to Hyde.

Since the All-Star break, the Celtics have the seventh-best defense, 27th-ranked offense. So they've basically done a full flip. — Jay King (@ByJayKing) March 9, 2017

Since that tweet and the debacle against the Nuggets on Friday, the Celtics are now 9th in defense and 26th on offense since Isaiah Thomas and Brad Stevens represented the Celtics in New Orleans. The numbers are the numbers, but let’s just take a little bit of a deep dive to gain some perspective. First of all, those are just rankings based on how the rest of the league is doing. If we know anything about Brad Stevens, it’s that he doesn’t worry about what’s happening in other teams’ locker rooms. The reality is, the Celtics have been equally effective (or ineffective depending on how you look at it) on both sides of the ball since February 24th with a 102.1 OffRtg and a 103.9 DefRtg. Some of that is based on competition. During that span, they’ve gone up against three top-10 defenses in Golden State, Atlanta, and Detroit and five top-10 offenses in again Golden State, Cleveland, Toronto, LAC, and Denver.

So what do we know? Has the team regained its defensive identity from last season with All-Defense first-teamer Avery Bradley back? Are the Celtics a good offensive team that’s been slumping of late? What can we expect when the playoffs start next month?

In the modern era of small ball and high scoring, Boston is uniquely prepared to defend.

Let’s look at the defense first since that seems to be the M.O. of this roster’s makeup. Outside of Isaiah Thomas and Kelly Olynyk, every player in the ten-man rotation is more or less a two-way player with a “defense-first” mentality. Boston’s greatest strength is on the perimeter with Smart, Bradley, Crowder, Brown, and Rozier. In the modern era of small ball and high scoring, Boston is uniquely prepared to defend. The win against the Warriors is a perfect example. There’s no doubt that the absence of Kevin Durant made a difference, but even with KD, Boston wouldn’t have changed their coverage of Steph Curry and Klay Thompson too much.

The Celtics—particularly Bradley and Smart—don’t get enough credit with how they negotiate screens. During the Big Three era, Doc usually opted to hedge pick-and-rolls because he had the length of Kevin Garnett and Kendrick Perkins to dissuade teams from turning the corner. Brad Stevens, on the other hand, opts to ICE PnRs and relies on his guards ability to fight through screens and recover quickly. Just like a running back hitting a hole in the line, Bradley and Smart understand that the low man wins. They’re masters of dipping their shoulders, getting under the contact, and using the screener as a hinge to whip around the pick.

Individually, they’re just so good in single coverage, too. Having Bradley healthy again makes such a huge difference. We saw it in those two big wins against Golden State and Cleveland where he singlehandedly shut down Kyrie Irving and Steph Curry in the fourth quarter. In a league dominated by scoring point guards, being able to put Bradley on them in crunch time is crucial. Couple that with the defensive versatility of Smart and Crowder to cover guys bigger than them and you’ve got a blueprint on how to beat some of the best teams in the NBA.

But that doesn’t mean they can stop everybody. After the blowout loss to the Nuggets, Stevens said that the Celtics are better equipped to deal with Golden State rather than Denver. He’s right. They struggle with size. Whether it’s Danilo Gallinari and Wilson Chandler or DeMar DeRozan or Russell Westbrook, Boston struggles with size. The good news is, you don’t have to face those guys every night; the bad news is they’ll face bigger teams in the playoffs. If the postseason started today, they’d draw Indiana in the first round and possibly Washington in the second. They’re both teams that outsize Boston, and as the pace slows in the playoffs, that could be a problem.

On offense, they seem to be just regressing to the mean. A lot of fans fell in love with the Celtics in January when they were on fire and went 10-4. They had a ridiculous OffRtg of 113.3 with Isaiah Thomas’ King of the 4th legend in full effect. He averaged nearly 33 points a game on 49.7% shooting including 43.2% from behind the arc.

The Celtics don’t lean on Thomas like fellow MVP candidates Russell Westbrook and James Harden, but Thomas is still the second leading scorer in the league, and it’s hard to ignore that his success is a microcosm of how the Celtics will do. However, while he’s the lead racer of the team, Al Horford has proven to be an integral part of the peloton and when he’s not on the floor, it’s evident why he’s worth every penny of his max contract. Stevens summed up the Al Horford effect best: “His presence makes unselfish basketball contagious.” Just look at Thomas’s numbers when Horford is on the floor. Per NBAwowy, Thomas is a more efficient scorer next to Horford, shooting 44.1 eFG% and 54% TS% with AH off vs. 52.9 eFG% and 59.2 TS% with AH on. Horford just makes the game easier for everybody.

While Isaiah Thomas is the lead racer of the team, Al Horford has proven to be an integral part of the peloton.

That’s the macro level look. Let’s put their symbiosis under the microscope. One of the ways the duo has adjusted to teams overplaying IT4 is by using dribble hand offs rather than playing pick-and-roll. A lot of the action is similar in their two-man game, but DHOs empower Horford to become more of a playmaker.

In a PnR, the ball handler’s dribble is live, so to some degree, it’s easier to guard because the defense can attempt to stop the dribble and effectively short circuit the ball movement. In a dribble hand off, the big has all three options available in the triple-threat position, and of all the bigs on the Celtics, Horford is the best above the break. He has a wide base to set brush screens, he can shoot 15 feet and out, he’s a willing passer at 6’11”, and he can put it on the floor.

We saw a lot of this against the Cavaliers. Thomas could basically catch the ball at full sprint as his defender (in this case, the slower Deron Williams) had to deal with a Horford-sized traffic cone creating space as Thomas blew by.

Horford has options for himself, too. With LeBron going way under the DHO, Horford drives on Channing Frye for the easy lay up. In their two losses in LA and Phoenix without Horford, Thomas couldn’t free himself up to drive as easily and seemed to always have a second defender on his hip.

But Thomas and Horford are just two pieces in a bigger puzzle. March has been Boston’s worst month of the season. Some of that has been a road-heavy schedule and the competition they’ve faced. Some of that has just been the growing pains of a bench unit made primarily of players on their rookie contracts and a starting lineup that’s only played 26 games together. For some perspective, The Herald’s Steve Bulpett got some great insight from Al Horford on the Celtics evolving offensive game and more importantly, their maturation:

“In the playoffs, teams turn up the pressure and the refs let you play a little more,” said Al Horford. “And when I was in Atlanta, what worked against them last year was that we turned on the heat against them. We pressured them and sped them up, and I think that teams have done that to us this year and it has affected us. “I think that if we can stay solid, composed, make the right plays and get good shots out of that, we’ll be in a good position. And I feel like we’ve improved in that area this year, but we still have to get better, and we have only a few regular season games to do it.”

Case in point, the fourth-quarter close at Golden State:

Even without Horford on the floor during some of that 15-0 run, you could see the team trusting each other on offense. They made the right basketball play, play after play after play. Against the Warriors switching defense, they made the right reads regardless of who was guarding them and always got an open shot. More so, they had composure. Check out Thomas at the 4:39 mark after the Celtics go up 11 and Steve Kerr calls for a timeout. You can see him motioning to his teammates to stay calm and not get too high.

On the flip side, Thomas has been vocal about pumping up guys like Kelly Olynyk in the post game. While Horford’s presence as a do-it-all vet helps the starting lineup, KO serves as his mirror image with the second unit, and his production is just as important, if not more so. After Olynyk put up 17/5/5 with 3 steals in his best performance of the season, Thomas said, "[Olynyk] means everything to me because that's another guy that can space the floor and, when he's hitting his shots, it's hard to guard because he has a really great pump fake and he can make plays as well. When he's playing like that, we usually win. We need him to play like that more and continue to be confident, which I know he will be and build on [Wednesday's] win." When Olynyk scores 10+ points in a game, the Celtics are a sparkling 20-4. Furthermore, per Basketball-Reference using John Hollinger’s GmScr ratings, if Olynyk doesn’t have a positive GmScr, the Celtics are 1-6. Two of those losses were on Boston’s last west coast trip. They’re 10-12 if he doesn’t have a GmScr over +5.

Again, Olynyk is just one player of many, but if you’re going to glean any positive analytic from Boston’s recent play as a collective, it should be this: the two starting lineups since the All-Star break with Avery Bradley or Jaylen Brown at shooting guard have net ratings of 2.3 and 28.3 respectively. That isn’t exactly Doc bragging that “we haven’t lost a playoff series with our starting lineup healthy,” but it’s an encouraging sign as the season winds down and the rotation potentially shortens heading into the playoffs. In fact, out of the ten most-used 5-man lineups since February 24th, only three of them have a negative NetRtg. Even lineups that are predominantly made up of bench players with Horford plus Smart-Rozier-Brown and either Olynyk and Jerebko are +11.7 and +27.7 respectively.

Sure, they’ve had some clunkers recently, but with the schedule lightening up and the team playing a large majority of their remaining games at the Garden, they should still be able to secure home-court advantage through two rounds of the playoffs. Or maybe they won’t. This is just the nature of these Celtics. They’re good, but they’re young. They play hard, but over an 82-game season, consistency has been an issue. But here’s the constant: Brad Stevens.

In the last two seasons heading into the playoffs, the Celtics have finished 10-5 and 9-6. If Boston can finish 2016-2017 with the same flourish, they’ll have their first 50+ win season in six years. Already, we’ve seen gains and development in Thomas’ meteoric rise to superstardom, solid production from Smart as an X-factor, and the blooming of Brown. And there are still sixteen games to go. Stevens’s Celtics have always been able to peak at the end of the year, so while things may seem shaky now, by April, we could be looking at a team playing their best on both sides of the ball and primed for a championship run.