There has been a lot of talk about the Celtics offense this season, specifically trying to diagnose what exactly what is going wrong. Everyone rightly expected this group of talented individual players to be able to score at a high level, but through 17 games, every offensive indicator has them performing poorly this season.
I think an overall comparison is interesting looking at last year's offensive numbers vs. this year's. I looked at numbers from basketball-reference.com.
2018-19 Celtics Team Offensive Metrics
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Offensive Four Factors |
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ORtg |
Pace |
FTr |
3PAr |
eFG% |
TOV% |
ORB% |
FT/FGA |
Team |
105.9 |
98.8 |
.215 |
.402 |
.506 |
11.8 |
21.3 |
.165 |
Lg Rank |
27 |
22 |
29 |
3 |
21 |
4 |
24 |
29 |
2017-18 Celtics Team Offensive
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Offensive Four Factors |
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ORtg |
Pace |
FTr |
3PAr |
eFG% |
TOV% |
ORB% |
FT/FGA |
Team |
107.6 |
96.0 |
.243 |
.357 |
.518 |
13.0 |
21.5 |
.188 |
Lg Rank |
18 |
22 |
18 |
8 |
15 |
15 |
18 |
20 |
As you can see from the above, the team is scoring at a lower rate (although it's worth remembering that they were below average on the year last year). They are playing a similar pace relative to the rest of the league (22nd both last year and this year). The league pace is up, probably due to the new rules on "freedom of movement" and the 14 second shot-clock reset rule. The Free Throw Rate and 3 point rate are interesting, and probably related. As you can see, last year, the team was going to the line more and shooting a lower percentage of their attempts from behind hte arc.
On the whole, this team wasn't particularly good at anything last year. They were pretty average to below average in all 4 Factors. Likewise, this year, they are shooting a lower eFG% and getting to the line less. It is interesting to note that they are turning it over at a very low rate, which I suspect is a result of them playing very passive on the offensive end. Not many opportunities to turn it over when you are passing the ball around the perimeter until you get an open jumper. That said, it's hard to fault them for taking good care of the ball without sounding like you are picking nits.
3 Point Shooting and Regression to the Mean.
There has been a lot made of the Celtics poor shooting performance. For a team that is taking more 3s than last year, going from 2nd to 20th in 3FG% has been disastrous. I find myself wondering whether their offense was just settling for more, lower quality 3s. I compiled the following numbers from stats.nba.com.
Celtics 3FGA Per Game by Closest Defender
Year |
Very Tight |
Tight |
Open |
Wide Open |
Total |
2017-18 |
0.3 |
3.3 |
10.5 |
16.0 |
30.1 |
2018-19 |
0.4 |
3.2 |
13.7 |
18.8 |
36.1 |
Difference |
+0.1 |
-0.1 |
+3.2 |
+2.8 |
+6.0 |
Based on the above, it looks like the extra 6 three point attempts the team is taking are all coming on "Open" or "Wide Open" shots. It's hard to say that they are shooting worse because they are getting worse looks. Given that fact, let's look at things from a pure "Regression to the Mean" perspective. What happens if we compare this year's team's attempts to last year's individual 3 point percentages?
Comparison between 2018-19 and 2017 - 18 3 point shooting
Rk |
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2018 3P |
2018 3PA |
2018 3P% |
2017 3P% |
Exp 3P |
DELTA |
1 |
Jayson Tatum |
29 |
75 |
.387 |
.434 |
32.6 |
+3.6 |
2 |
Kyrie Irving |
40 |
101 |
.396 |
.408 |
41.2 |
+1.2 |
3 |
Al Horford |
20 |
67 |
.299 |
.429 |
28.7 |
+8.7 |
4 |
Jaylen Brown |
19 |
69 |
.275 |
.395 |
27.3 |
+8.3 |
5 |
Gordon Hayward |
17 |
60 |
.283 |
.398* |
23.9 |
+6.9 |
6 |
Marcus Morris |
32 |
72 |
.444 |
.368 |
26.5 |
-5.5 |
7 |
Marcus Smart |
16 |
53 |
.302 |
.301 |
16.0 |
- |
8 |
Terry Rozier |
22 |
63 |
.349 |
.381 |
24.0 |
+2.0 |
Totals |
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+25.2 |
* I used Hayward’s 3FG% from his last full season since he didn’t play last year. stats courtesy of basketball-reference.com.
As you can see from the above chart, if the top 8 guys on this year's team were shooting last year's percentages, this team would have hit an extra 25.2 threes on the season. This might not sound like much, but over 17 games, that's an extra 4.4 points a game, which would raise their Offensive Rating to 110.5, good for 11th place. That's still not the elite offense we are looking for, but it's a lot better than 27th, right?
The other challenge I'm seeing is that this team isn't attacking the rim like they need to. They are currently 29th of 30 teams in FGA at the rim (only Golden State is worse). Over the last 4 games, we are averaging 30.3 attempts in the restricted area, vs. 23.1 over the first 13 games. I feel this is a point of emphasis,and this is already starting to take care of itself.
On the whole, most of Boston's offensive struggles are just a result of statistical variance on their 3 point shooting. This team is generating shots that are good enough to be a top 10 offense, and that's with their 2nd best player still largely playing on 1 leg. I suspect that we are going to see the team right the ship in the upcoming 10 - 12 games against a pretty soft schedule.