The Boston Celtics are the overwhelming title favorites, but should they be?

The Boston Celtics are deservedly the runaway favorites to win the title. They own the best record (51-14), net rating (plus-11.4), offensive rating (122.7), and simple rating system score (11.13) in the league, and the gap between them and the second-place team is massive. 

*2nd Rank Gap is the gap between the Celtics and the second-ranked team applied to the second-ranked team

When it comes to team metrics, the Celtics have no current rivals and are instead chasing history. 

The Celtics are chasing history

The Celtics are in the midst of a historic season. They’re fifth All-time in Simple Rating System score (SRS), the sum of a team’s margin of victory and strength of schedule, fourth all-time in net rating, and are on pace to set the NBA single-season offensive efficiency record and become just the 26th team to reach 64 wins in a season. The Celtics are not just the best team in the NBA right now, they’re one of the greatest teams ever assembled, but anything less than a championship could wipe it all away. 

The reality of NBA discourse is the 2023-24 Celtics won’t be viewed as a historic team without winning a title. As much as rings-culture has unfairly obscured great individual careers, it has also tarnished great teams. No one cares that the 1993-94 Seattle Supersonics won 63 games because they lost in the first round of the playoffs. If mentioned at all, they’ve come to personify failure, even though that team was nothing short of a rousing success. 

Everything the Celtics achieve this regular season will be on the line in the playoffs. They could go down as one of the greatest teams ever, or they could become a punchline. Nuance, like Lou Williams, is a non-starter. The Celtics, fortunately, have a lot of factors working for them in their pursuit of glory, but one flaw could undo it all. 

The Celtics’ SRS and net rating are championship harbingers

Simple Rating System (SRS) isn’t a perfect metric, but it does a better job than win-loss record at identifying truly elite teams. Take the 2021-22 Phoenix Suns as an example. They won an NBA-best 64 games, the same pace as the 2023-24 Celtics, but only had a SRS of 6.94, second in the NBA. While they were the favorites in the Western Conference, it shouldn’t have been a huge shock when they were upset in the second round of the playoffs by the Dallas Mavericks. 

Those Suns were still an excellent team, but their SRS was more indicative of their true talent level than their record. Of the 78 teams to win 60 or more games, they owned the 49th-best SRS, and of the 25 teams to reach 64 or more wins, they had the 24th SRS, which they only secured due to the 2005-06 Pistons playing at a 13-possession slower pace. However, the 2023-24 Celtics’ SRS suggests their record is no fluke. 

If the Celtics maintain their SRS of 11.13, they’d be just the fifth team to finish a season with an SRS of 11 or greater. SRS isn’t a perfect predictor of championship success, but when a team grades out as highly as the Celtics, they win the title. All four teams who posted a SRS over 11 ended their season crowned champions.  

Even if the Celtics were to slip in SRS towards the end of the season, only 10 teams, not including these Celtics, have ever finished with an SRS greater than 10, and seven of the ten teams won it all. However, that’s despite two teams from the same season showing up twice, meaning of the eight available championships, seven were won by the team with an SRS greater than 10. The lone exception was the 2015-16 season when the LeBron James-led Cleveland Cavaliers turned around a 3-1 series deficit against the 73-win Golden State Warriors and the San Antonio Spurs were upset in the second round of the playoffs by the Memphis Grizzlies. 

Based upon SRS, the Celtics should be considered a virtual lock for the title. Historically, teams this overwhelming can’t be tripped up by a bad matchup. The Celtics have reached the territory of regular-season dominance where they need to be considered an inner-circle All-Time great team. 

SRS believes the Celtics are by far the best team in the NBA, but net rating, which closely mirrors SRS, tells a fascinating story about the Celtics’ championship chances. Ten teams have finished a season with a greater than plus-10 net rating, and eight won the title. The lone exceptions, again, are the 2015-16 Spurs and Warriors. The Celtics’ net rating of plus-11.4 is the fourth highest of all-time, behind only the 1995-96 and 1996-97 Chicago Bulls and the 2016-17 Golden State Warriors, three teams widely considered to be the greatest in NBA history. 

While securing a net rating of greater than plus-10 is an incredible indicator of championship upside, slipping to plus-10 and below, for teams in the top 20 all-time of SRS, has only produced one champion out of nine teams, the 1985-86 Celtics. 

Right now, the Celtics’ net rating is plus-11.4, but they still have 17 games left. It’s unlikely their net rating will slip to plus-10 or worse, but it’s a figure worth monitoring over the final month of the season. It won’t stop them from being the best team in the league or lower their championship favorites status, but it could indicate they’re not as inevitable as they seem today. 

The teamwide metrics have all but crowned the Celtics the 2023-24 champions. However, these Celtics differ in a sizeable way compared to their historically elite brethren. The 2023-24 Celtics don’t have the top-end talent that most elite teams employ, and that matters a lot. 

The Celtics’ weakest link is their strongest link

A common trope you’ll hear is to never bet against the best player in a series. Basketball is unique for a team sport because just one player can dramatically shift your odds, even in the face of a superior opponent. While the Celtics have a roster full of excellent players, the top of their roster comes up short compared to other historically great regular season teams. 

Of the six teams to finish a season with a net rating of plus-11 or greater, their best player’s Box Plus-Minus (BPM) was on average 9.2 and ranked, on average, 2.1 in the league. The lowest BPM from that group was Kevin Garnett’s 8.2 in 2007-08, ranking fourth on the season. The 2023-24 Celtics’ best player by BPM is Jayson Tatum at 5.2, which ranks 11th. 

Even when we remove the elite teamwide success threshold, Tatum being a title team’s best player stands out. Over the past 10 champions, the average BPM of their best player was 8.4 with a median of 8.65. The only teams with a player with a sub-6.0 BPM to win a title over the past decade are the 2013-14 San Antonio Spurs and the 2021-22 Golden State Warriors, which aren’t great proxies for these Celtics. 

Both the Spurs and Warriors retained the aging core of their previous dynasty and supplemented it with younger role players. While a young Kahwi Leonard led the 2013-14 Spurs in BPM at 5.1, he had two-time MVP Tim Duncan, along with Hall of Famers Manu Ginobili and Tony Parker, supporting him. 

The 2021-22 Warriors were still led by Stephen Curry, who despite his 5.4 BPM that season, was coming off an 8.7 BPM season in 2020-21, and produced a 7.5 BPM in the season after their championship. Jayson Tatum is an excellent player but has maxed out at a BPM of 5.5, which is a pretty significant step below the usual best player by BPM on a champion. 

Can the Celtics egalitarian juggernaut win it all?

The Celtics have built a truly unique juggernaut, and their front office should be applauded. No team in history has been as dominant in the regular season without one player carrying a much more significant load. Even though the Celtics lag behind in BPM produced by their best player, they make up for it by being comfortably better from players two through five, compared to recent champions, and that doesn’t include Jaylen Brown, whom BPM has never viewed kindly. 

The Celtics’ strongest link might be their weak link, but the depth of their talent is unparalleled. The dispersal of production compares best to the 2013-14 Spurs, who were absolutely dominant and a beautiful team to watch. It remains to be seen if these Celtics can lean into the strength-in-numbers approach the Spurs’ employed, but the blueprint does exist.  

NBA history has taught us that there is no singular championship formula, and these Celtics are attempting to forge a new path in plain sight. They’re a juggernaut without a singularly dominant player, which we’ve never seen at this level. The Celtics, as a collective, have all the markings of a champion, but their lack of a transcendent individual would make them a championship anomaly. 

Teams have punched above the weight of their best player, but those teams were never far and away the best team in the league, nor the championship favorites. The Celtics deserve to be championship favorites, but their hold on the distinction is more tenuous than one would assume. In these playoffs, history is on the line for the Celtics, and we’ll see if the collective is up for the challenge.