Here are evaluations of the Celtics’ starters for this past season. The grades are based on whether a player reached his potential, not his general skill level.
Robert Williams: B
The lower grade is based mostly on his durability. Williams battled left knee tendinitis early in the season and then tore the meniscus in that knee in March. He underwent surgery and returned just under a month later but was clearly hobbled during much of the playoffs. By the end of the NBA Finals against the Warriors, though, he was moving well and had seemed to return to his above-the-rim self.
Williams took the next step in his ascension as an elite rim protector and received second-team All-Defense recognition. He averaged a career-high 2.2 blocks per game, third in the NBA. And when he was the primary defender, opponents shot just 51.9 percent from the field within 6 feet of the basket, 11.2 percent below their averages in those situations.
Also, the Celtics outscored opponents by 7.5 points per 100 possessions with Williams on the court during the playoffs, the best mark among the starters. There is no urgency, but Williams has a decent jump shot and made a career-high 73.6 percent of his free throws. It would become an asset if he can extend his range a bit. This season, just 1.3 percent of his shots came from mid-range, a career low. But a career-high 30.6 percent of his shots were unassisted, showing that he is not just throwing down lobs. As long as Williams can stay healthy, his four-year, $48 million extension that kicks in next season will be a bargain.
Marcus Smart: B+
After years of working, hoping, and occasionally campaigning, Smart was named the NBA’s Defensive Player of the Year, becoming the first guard to win the award since Gary Payton since 1996. It is a significant accomplishment, and Smart was the backbone of the Celtics’ league-leading and relentless defense.
Still, he remains one of the more polarizing Celtics in recent memory, with questions arising about whether he should be the lead conductor of an offense built around Jayson Tatum and Jaylen Brown for years to come.
No, Smart was not perfect at that end of the floor, and his bad 3-point shooting games seem to stand out more than the others, but he was darn good overall. And most of all, he seems aware of his faults and willing to shift to areas in which he is most effective.
This season, 42 percent of his points came from 2-point range, his highest mark since 2015-16, and he attempted 20.9 percent of the Celtics’ 3-pointers, the second-lowest portion of his career. He also averaged a career-high 4.9 points in the paint. His overall field goal percentage rose for the second consecutive season.
In addition to averaging a career-high 5.9 assists, Smart’s respectable 2.6-to-1 assist-to-turnover ratio ranked ahead of point guards such as Fred VanVleet, Jrue Holiday, Trae Young, and Shai Gilgeous-Alexander.
Al Horford: B
All of the Celtics wanted to win a championship, of course, but based on the unusual amount of emotion he showed throughout the playoffs, no one wanted it more than Horford, who relished making his first Finals.
It was a strong bounce-back for the 36-year-old forward after a lost season with the Thunder. He remains an excellent defender and didn’t get enough credit for his role as an anchor in the Celtics’ top-ranked attack. He is still capable of switching on to guards on the perimeter — even if that didn’t always end well against Stephen Curry — and he averaged 2.2 blocks per 100 possessions, his highest mark since 2015-16.
For much of the season, it appeared that Horford’s 3-point shot had regressed despite the fact that he was again getting open looks. A career-high 46.6 percent of his shots came from beyond the arc, but he made 33.6 percent during the regular season. He followed that with a blistering postseason in which he connected on 48 percent from long range, buoyed by a 6-for-8 performance in the Game 1 win over Golden State.
Given Horford’s age, and the years of wear and tear, it’s fair to wonder how long he can keep this up. But the Celtics will likely limit his regular-season minutes even more in order to keep him fresh and healthy for when he is needed most.
Jaylen Brown: B+
Brown and Tatum silenced any questions about whether they can be a championship-caliber pairing for the long term. Brown was passed over for an All-Star nod after making the squad a year ago, though his hamstring injury and the Celtics’ early struggles dented his chances.
There were stretches in games when Brown appeared to be the best player on the court. But too often a powerful quarter was followed by stretches in which he seemed to disappear. The next step in his development will be more frequent sustained dominance within a game.
Brown’s ballhandling has actually improved, but he often appeared discombobulated when he drove into traffic and coughed up some puzzling turnovers. He is at his best when the ball is moving. When taking a shot after having possession for less than two seconds, Brown made 63.3 percent of his attempts. When he had the ball for six seconds or more, that number fell to 48.8.
The Celtics would benefit from getting him into transition more, where he can use his athleticism to punish defenders. This season, 13.5 percent of Brown’s points came on fast breaks, a career low, and 41.8 percent of his points came in the paint, the second-lowest mark of his career. And he was excellent in the paint during the playoffs. The Celtics need to unlock that area of his game more.
Jayson Tatum: A-
By most measures, this season was a roaring success for Tatum. He started the All-Star Game, was named first-team All-NBA, and nearly led the Celtics to a championship. And his advanced numbers during the regular season were startling. With Tatum on the court, the Celtics had a plus-12.1 rating. When he was on the bench, it was minus-1.9, the only negative off-court rating for a rotation player. A 14-point net rating differential is massive.
Still, the lasting memories for Tatum could end up being his uneven postseason and his forgettable Finals. He set an NBA record with 100 turnovers during the playoffs and made 36.7 percent of his shots in the Finals, including just 31.6 percent of his 2-pointers.
Defenses designed game plans around stopping Tatum, but that is hardly a new approach to slowing someone of his caliber, and true superstars find a way to thrive. Tatum made strides as a playmaker and deserves credit for frequently making the right decision rather than forcing the issue against multiple defenders. And it’s easy to forget that he is just 24. But the bar is high.
Like Horford, Tatum probably does not get enough credit for his defense. His 103.4 regular-season defensive rating was tied with Williams for tops on the team, and he could become an All-NBA defender. It will be interesting to see how quickly he shakes off this season’s tough finish.