BOSTON -- Regardless of how the Boston Celtics roster has changed in recent years, the team's defense has been among the more constants to factor in the team's consistent level of success.
But the roster upheaval this offseason will impact the team on several levels, none more noticeable than the team's defense.
Gone are Al Horford and Aron Baynes, two pillars of elite defensive consistency that Boston has no one remotely close to filling their enormous voids currently on the roster.
And while most of the NBA is shifting towards being more offensive-minded, defense still rules the day when it comes to winning it all.
Of the last 10 NBA champions, nine ranked among the league's top 10 in defensive rating with the lone exception being the 2018 Golden State Warriors whose defensive rating that year was 11th in the league.
And while winning an NBA title is certainly a goal for Boston, few if any outside of the franchise - and even they are full of those who are skeptical - believe this team as it is constructed can win an NBA title.
While that remains to be determined, one thing we know for sure is if it were to happen it would most likely involve their defense playing significantly better than expected.
Here are five factors that would have to come into play if the Celtics were to deliver a top-10 caliber defense this season.
CONTEST MORE SHOTS
Like most things when it comes to defense, achieving this end will be a lot easier said than done. One of the reasons the Celtics have been one of the better teams defensively under seventh-year coach Brad Stevens has been due to the team's ability to take away open looks often.
According to NBA.com's advanced stats, the Celtics' defensive field goal percentage has ranked among the NBA's top 10 each of the last four seasons while being among the top 4 each of the last two. Being able to maintain a similar ranking this season will go far in Boston's efforts at remaining a top-tier team defensively.
DEFENSIVE FIELD GOAL PERCENTAGE
44.9% in 2018-2019 (4th)
43.9% in 2017-2018 (2nd)
45.0% in 2016-2017 (9th)
44.2% in 2015-2016 (8th)
45.0% in 2014-2015 (17th)
46.4% in 2013-2014 (22nd)
POINTS OFF TURNOVERS
Contesting shots is important, obviously. But the Celtics have to do a better job of making teams pay for making mistakes; specifically finding a way to generate more offense off those miscues.
Last season was indeed a breakout season for the Celtics defensively in this category with 16.1 percent of the team's offense coming off turnovers which ranked sixth in the NBA.
Only once prior to that in Brad Stevens' six seasons in Boston had the team a higher percentage (17.8 percent in 2015-2016, ranked fifth in the NBA) of points off turnovers.
Boston has the firepower to hold its own most nights with whoever they face. But the Celtics ability to not only take away opponent points by forcing turnovers but to also convert them into points, is what this defense desperately needs to happen this season.
PERCENTAGE POINTS OFF TURNOVERS (YEAR AND NBA RANK)
16.1% in 2018-19 (6)
14.8% in 2017-18 (21)
15.1% in 2016-17 (18)
17.8% in 2015-16 (5)
17.1% in 14-15 (11)
I know, I know. Enes Kanter isn't exactly the first name that comes to mind when you talk about defense. But for Boston to have the kind of season that involves above-average play defensively, Kanter will have to dominate on the boards. The Celtics are going to need his inside presence, not only when it comes to scoring but also controlling the glass at both ends of the floor.
In his ninth season, Kanter has ranked among the NBA's top-six in offensive rebounds per game in four of the last five seasons. The stress that the 6-foot-11 center puts on teams with his play and activity, has the potential to wear teams down and thus make them less effective on offense and thereby bolstering the efforts on Boston's part to be a good team defensively.
AN EMERGING 3-AND-D GUY
When it comes to playing a better-than-expected brand of basketball defensively, there has to be a player or two who takes his game at that end of the floor to a different level after having already shown signs of promise. The Celtics have a player like that in Semi Ojeleye, a 6-foot-6 rock of a human with the kind of lateral quickness you rarely see on a body as muscular as his. But for him to really make an impact on this team more so than we've seen thus far, he has to become a more consistent 3-point threat in addition to elevating his game defensively and more than just another body to throw at Giannis Antetokounmpo. His emergence as a reliable 3-and-D guy will go far in Boston's hopes of remaining one of the better teams defensively in the NBA.
A HEALTHY MARCUS SMART
There's a reason why - OK, quite a few reasons why - Marcus Smart is the longest-tenured member of the Boston Celtics roster now. There are very few people in the NBA with the ability to impact games the way Smart can. He's not a great shooter, but more times than not makes big ones in big moments. His defensive stats are really good, but won't blow you away and yet there he is, time after time, making the best plays defensively when his team needs him most. Boston will need that and then some from Smart who is coming off a season in which he played in a career-high 80 games.
Smart playing a full or near-full 82-game slate is absolutely vital to Boston's chances of being among the top teams in the Eastern Conference. Defense has to be the one area of growth we see with this group all season. And the example of that need for growth and the need for a defensive mindset begins with Smart who is the one player from their core that would be the most difficult to replace or replicate what he brings to the game.
Click here to download the new MyTeams App by NBC Sports! Receive comprehensive coverage of your teams and stream the Celtics easily on your device.