How can the Boston Celtics get back in contention with new head coach Ime Udoka?
ESPN's Adrian Wojnarowski reported Wednesday that Celtics president of basketball operations Brad Stevens has chosen Udoka, who had been an assistant with the Brooklyn Nets, as his successor on the sideline.
Udoka becomes just the third Boston coach in the past 17 years. The Celtics won a title under Doc Rivers and reached the Eastern Conference finals three times in Stevens' eight seasons as head coach, most recently less than a year ago.
After a disappointing season that ended in a first-round exit to his Nets, how can Udoka help a revamped roster get back on track and repeat that kind of playoff success? Let's take a look.
Rebuild defensive identity
As much attention was put elsewhere, a fundamental reason Boston declined by 12 wins from 2019-20 to 2020-21 was the team's defense with key players on the court. In 2019-20, the Celtics ranked in the 92nd percentile defensively, according to Cleaning the Glass, with Jaylen Brown, Marcus Smart, Jayson Tatum and Kemba Walker all on the court.
Despite injuries, that group actually played slightly more possessions together this season and dropped to the 2nd percentile on defense. Considering just Brown, Tatum and Walker to produce a larger sample, the decline is less dramatic (from the 85th percentile to the 24th) but still evident.
In part, Boston was probably a victim of unsustainably hot shooting. Opponents made 39% of their 3-point attempts against the Celtics' three All-Stars. Only one team (the Minnesota Timberwolves) saw opponents shoot so well over the course of the season. Still, that's notable because Boston had been such an incredible outlier in terms of how poorly opponents shoot 3s against them.
Across the tenures of both Rivers and Stevens, the Celtics had ranked in the bottom 10 in opponent 3-point percentage every season between 2007-08 and 2019-20, posting the lowest mark in the league three times and the second-lowest three others. This season, Boston's opponent 3-point percentage ranked 22nd.
Although not responsible for the entirety of the decline, opponent 3-point shooting was the biggest reason the Celtics' defensive rating went from fourth lowest in the NBA during the 2019-20 regular season to 13th in 2020-21 -- a far bigger drop-off than the team experienced on offense with the departure of free agent Gordon Hayward, who was replaced primarily by unproven recent draft picks.
Last week's trade that swapped out Walker to bring back Al Horford should help Boston defensively. Despite giving effort at that end, Walker's size at 6 feet made him a target for opponents. Horford gives Boston another versatile defender at center as well as an alternative at power forward against bigger opposing frontcourts.
Even if the Celtics can't rediscover whatever they were doing differently from opponents to contest 3-pointers -- or if their streak was more about random chance than gaming the system -- their defense should benefit from the pull of regression on open shooters. Merely average 3-point shooting by opponents would boost Boston's defense by about a half a point per 100 possessions.
Create more shots for others
Much of the hand-wringing about the 2020-21 Celtics stemmed from the team's lack of ball movement. Indeed, Boston's rate of assisted field goals ranked 27th in the league. That's not automatically a bad thing. Two of the three teams behind the Celtics, the Dallas Mavericks and Portland Trail Blazers, were among the league's top eight in offensive rating. (Boston, at 10th, wasn't far behind.)
Still, there's reason to believe the Celtics could be even better by setting each other up more often. According to Second Spectrum tracking data on NBA Advanced Stats, Boston was far more elite when it came to shots with less than two seconds of touch time -- typically shots off assists. The Celtics' 60.5% effective field goal percentage (eFG%) on those attempts ranked sixth in the league.
When it came to self-created shots with more than two seconds of touch time, Boston's eFG% dropped substantially to 49%. Every team is less efficient on self-created shots, but that was true of the Celtics even relative to the league. Their eFG% on self-created attempts was 12th best in the league. So it's a concern that just two teams (Portland and the New York Knicks) took a higher percentage of their shots after at least two seconds of touch time than Boston's 53%.
Here, Udoka's experience with the Nets should be advantageous. Despite their collection of stars, Brooklyn still had the league's eighth-lowest rate of self-created shots. The Nets were able to leverage the attention paid to Kevin Durant, James Harden and Kyrie Irving to create opportunities for their less-heralded teammates. The Celtics could benefit from doing the same.
Develop young talent
While the defense may go further to determine Boston's ability to bounce back next season, Udoka's most important task in the long term is guiding the Celtics' recent first-round picks into larger roles to support the team's high-paid stars.
Boston's cupboard is hardly empty. Point guard Payton Pritchard averaged 19 MPG as a rookie, solidifying the backup spot, while Robert Williams III moved into the starting lineup after the Celtics traded starting center Daniel Theis at the deadline, and Grant Williams was one of Stevens' most trusted reserves. Further down the rotation, wings Romeo Langford and rookie Aaron Nesmith showed flashes, including Langford starting the last two games of Boston's playoff series against Udoka and Brooklyn.
It's not reasonable to expect all of these picks -- most of them were made in the middle of the first round -- to pan out. But the Celtics need at least a few to step forward as starters or key reserves to manage the team's cap sheet with both Brown and Tatum on max rookie extensions.
As Boston starts to make decisions on some of these players, the urgency for them to develop accelerates. Robert Williams is eligible for a rookie extension this fall, with Langford and Grant Williams a year away from that pivot point.
Along with the Mavericks opening, the Celtics coaching job loomed as one of the most attractive for a first-time head coach because of the franchise's track record of stability on the sideline and in the front office, as well as the All-Stars headlining the roster.
If Udoka can help Boston make incremental upgrades at both ends of the court, there's enough talent for the Celtics to get back in contention for home-court advantage in the first round of the playoffs next season and beyond.