How much will Marcus Smart’s defense be missed by the Boston Celtics?

In what was monumental news this summer, the Boston Celtics traded long-time veteran guard and 2022 Defensive Player of the Year Marcus Smart. Effectively, the Celtics had too many guards and needed another big, which they got in Kristaps Prozingis. The move was a risk for a variety of reasons involving the player leaving, the one coming in, and even one that was nearly traded but wasn’t.

Along with Smart’s DPOY award, he also has three All-Defensive First team selections in 2019, 2020, and 2022. He is well known as a very switchable and tough defender, not shying away from difficult matchups, and putting his body on the line in the form of taking charges and diving for loose balls.

Now, as training camp is set to begin very soon, one big unknown surrounds the question of defense. Trading an award-winning defensive player will no doubt have an impact.

The question is, just how much?

Looking at last year, Smart’s defense wasn’t 100% compared to past seasons. Granted he was dealing with an injury but even in the playoffs and it was clear he wasn’t the same. Despite Smart’s decline, the Boston Celtics still finished third overall in adjusted defensive rating per Dunksandthrees.com.

Obviously, this is largely because of the C’s overall team defense. NBA defenses are more of a five-man effort than anything else. Looking within the backcourt next to Smart as another member of most five-man lineups is Derrick White. White played very well last season and even better in Smart’s injury absence. He was selected to the All-Defensive Second team, led all guards in blocks, and contested 2-point shots. Now he will be stepping into the starting point guard role full-time instead of starting next to Smart at the shooting guard spot.

So the question now becomes: will White be able to handle the defensive backcourt without Smart next to him?

The Boston Celtics will rely on team defense to overcome loss of Marcus Smart

As mentioned defenses are a five-man effort. White won’t be by himself but still, it’s worth taking a look at how White has done without Smart on the floor.

Per Cleaningtheglass.com lineup data, the Boston Celtics defense performed well with with Smart sitting and White leading the defense. They held teams to 106.1 points per 100 possessions on average which is very good, ranking 97th percentile. The best lineup was one that featured White as the only guard along with Jaylen Brown and Jayson Tatum on the wings and Al Horford and Rob Williams down low.

That five-man group crushed teams giving up only 78.7 points per 100 possessions. Now look at that same group but sub-White out for Smart and it swings to 123 points per 100 possessions. Granted those lineups only played 143 and 180 possessions together respectively, and the swing is large enough that it raises even more questions, but it’s still not nothing.

What also needs to be taken into account is the extra big that is coming into the starting lineup. Putting Porzingis at the center spot allows for a similar lineup as mentioned above, with White, Brown, Tatum, and either Williams or Horford filling out the ranks. That’s a group with a lot of size and a lot of reach. Porzingis, while he hasn’t been the most reliable over his career is coming off of a great season. Defensively he was +1.2 in estimated plus/minus putting him in the 85th percentile for centers, per Dunksandthrees.com. That is distinctly above average. This will hopefully give the team more opportunity to play these big lineups that White appeared to do so well in. Where White really shines is in his switchability, especially on larger opponents. This gives the defensive rotation extra room to breathe and veer off into position or provide help.

So combining Whites’s defensive prowess along with Tatum and Brown’s size and athleticism on the wings, Porzingis or Williams protecting the rim, and Horford acting as the connective tissue, this Celtics team doesn’t look all that vulnerable. The big concern will of course be if they can maintain the health of their bigs. The hope of acquiring Porzingis is that it gives the Boston Celtics an effective three-man big rotation that can give the appropriate amount of rest when needed to hopefully curb injury potential.

Smart is no doubt still a good defensive player and will be for the Memphis Grizzlies, but adding a big like Porzingis was a trade-off that makes sense. It probably only makes sense when having a player like White though, who is no stranger to carrying the load and has done so in both Boston and San Antonio previously.