Boston Celtics on Pace for Worst Defensive Season Since 2013-14
Matthew J. Lee | The Boston Globe via Getty Images
The Celtics do not have a top 15 defensive rating in the NBA. This year will mark the first time since 2013-14 that this statement holds. In 2013, Brandon Bass led the team in win shares (5.1), and the team went 25-57. That team’s defensive rating was 106.5. Boston’s this year? 112.0.
Now, there clearly must be more context added to those statements. NBA teams averaged 101.0 points per game in 2013, and that number is up to 112.1 in 2021. The Celtics also dealt with more COVID issues than any other team, losing 167 player days this season. Regardless, those factors do not excuse the worst defensive season in the last seven years.
Boston allows 111.4 points per game this season, up 4.1 points from last year, 3.4 from 2018-19, and 11.0 from 2017-18. Teams shoot 46.6% against the Celtics and 37.7% from three. These numbers also vastly increased from prior seasons - 44.1%/34.0% last year, 44.8%/34.4% in 2018-19, and 44.0%/33.9% in 2017-18.
Despite this, Boston remains a top ten paint defense. They give up 44.2 points in the paint per game (5th in NBA) and only allow 22.9 shots per game in the restricted area (2nd in NBA). Perimeter defense is letting the Celtics down.
The team’s three-point defense declined this year. In recent weeks this trend became more noticeable as notorious three-point threats continue to get open looks. Over the team’s last four games, Duncan Robinson, Kevin Love, and Coby White combined to take 28 open/wide-open three-pointers against the C’s.* The trio shot 40 total threes in these games, meaning 70% of their shots from range were open/wide open, and Robinson accounted for 11/12 of those that were not. They shot 19/28 (67.9%) on their open/wide-open looks.
*According to the NBA, open looks are when a defender is 4-6 feet away, and wide-open looks are when a defender is 6+ feet away
The threesome shoots an average of 38.4% from deep on the season and still managed to be open 70% of the time vs. Boston. Whether rotations are slow or coverages are being missed, the Celtics cannot sustain this sort of defense if they hope to win games.
The loss of Gordon Hayward has also severely impacted Boston’s perimeter defense. Hayward was the primary defender on most team’s second or third options last season; Tobias Harris, Khris Middleton, and Fred VanVleet are the most notable examples. This season those players’ primary defenders have been Marcus Smart, Jaylen Brown, and Kemba Walker, respectively. In turn, less qualified players are forced to take on larger challenges as matchups shift.
This issue also led to almost every individual player being a worse three-point defender this year. Smart went from allowing 36.1% from deep to 36.9%. Jayson Tatum went from 35.9% to 37.8%. Brown from 36.0% to 37.5%. Walker from 36.1% to 37.6%. Even Evan Fournier's comparison (37.9%) to Hayward last season (36.7%) is a downgrade.
Boston contested 26.3 threes per game last year (7th in the NBA). This year the number dipped to 20.8 (16th in NBA). They got 16.7 deflections per game last year (3rd in NBA), but only 14.7 this year (11th in NBA). Defensive numbers have deteriorated across the board.
Brad Stevens always led defensive-minded teams. He put a focal point on perimeter defense, and the team always responded. This year that has not been the case. The Celtics’ defense currently allows more points than ever before. They say defense wins championships. If that’s the case, the future is bleak in Boston.
