Celtics roster evaluations, Part 2: Bench players and occasional starters

Evan Fournier shot 44.8 percent from the field in 16 regular-season games with the Celtics.Matthew J Lee/Globe staff

This is the second in a three-part series of individual evaluations of the Celtics. This section includes key bench players and occasional starters. Players are graded based on the expectations within their roles.

Part 1: Grading Semi Ojeleye, Carsen Edwards, and other non-rotation players

Evan Fournier: B-plus

Fournier had a challenging few months with the Celtics after being acquired from the Magic on March 25. He went 0 for 10 in his Boston debut and was diagnosed with COVID-19 less than a week later. He missed nine games because of the virus and struggled mightily after his return, later revealing that he was experiencing aftereffects that mimicked concussion symptoms, such as headaches and blurred vision.

Those issues eventually subsided, and when Fournier was on the court and feeling fine, he played pretty well. The veteran made 46.3 percent of his 3-pointers with the Celtics, including a blistering 22 for 39 (56.4 percent) over his last five games of the regular season.

He seemed to develop good chemistry with Kemba Walker in particular and was a good outlet when the stars faced extra attention. The Celtics outscored opponents by 3.5 points per 100 possessions with Fournier on the floor, the best net rating among regular rotation players.

Romeo Langford: Incomplete

Langford’s first two NBA seasons have been defined more by what has kept him off the court than what he has done on it. He missed the first half of this year after undergoing offseason wrist surgery. Then when he was cleared to return in March, he contracted COVID-19, extending his absence.

Still, Langford is just 21 years old, and the Celtics remain hopeful that he can be impactful, especially if he is able to remain healthy for an entire season. He has shown his value as a defender who is capable of sticking with athletic wings and guarding multiple positions.

His offensive game remains raw, and opponents know it. Langford will get plenty of open looks from the corners until he proves he can make his line-drive shots consistently.

Langford slipped out of the rotation a bit later in the season before being called on to start playoff games in place of the injured Walker. He scored 17 points in the playoff finale.

Payton Pritchard: B

The 26th overall pick in last year’s draft was a revelation when Walker was sidelined at the start of the season. He shot 60.7 percent from the field and 55.6 percent from the 3-point line in five December games and won a January road game against the Heat with a last-second putback.

He was clearly unfazed by the transition from college, as evidenced by his penchant for spotting up for jumpers from well behind the 3-point arc.

Pritchard may have caught the rest of the NBA off guard, but defenses adjusted as the season progressed. His shooting and assist numbers both dipped after the All-Star break. At the other end of the floor, opponents consistently looked to exploit matchups against the 6-foot-1-inch guard, often with some success.

Pritchard is a relentless worker, so expect him to dedicate much of this offseason to figuring out how to be more of a factor on defense.

Aaron Nesmith: B

When the Celtics selected Nesmith with the 14th overall pick in last year’s draft, they hoped the sharpshooter could provide some instant scoring pop off the bench. He made more than 50 percent of his 3-pointers during an injury-shortened season at Vanderbilt a year ago.

But the speed of the NBA game seemed to overwhelm Nesmith at the start, and his confidence in his shot suffered, too. All along, Celtics coaches and executives praised Nesmith’s work ethic, and his determination paid off as he seized an important role in the second half of the season.

Nesmith’s shooting improved, but he made his most significant impact with hustle. He would fly out of nowhere to go for a blocked shot or steal, and he gave some spice to Boston’s fast-break attack. Sometimes his aggression was a bit uncontrolled, however, and it led to foul trouble. He didn’t play enough for that to be an issue, but it could become one if his role expands.

Tristan Thompson’s fit with the 2020-21 Celtics appeared wobbly at times but he added some much-needed toughness, and his ability to battle for offensive rebounds was unmatched.Jim Davis/Globe Staff

Tristan Thompson: C

In a vacuum, the Celtics’ decision to trade center Daniel Theis to the Bulls made little sense. Theis had a better grasp of Boston’s system at both ends of the floor than Thompson and was a better complement for the team’s skilled scorers. But Theis was set to become a free agent, and the Celtics wanted to get below the luxury-tax threshold to delay the even costlier repeater tax, which is activated when a team is in the tax three of four seasons.

Thompson’s fit with this group appeared wobbly at times but he added much-needed toughness, and his ability to battle for offensive rebounds was unmatched on this roster.

As the season progressed, Thompson did a better job of gobbling up missed shots and whistling passes to teammates rather than forcing up contested attempts inside. Nevertheless, it became clear that if Robert Williams is healthy, he will be the starting center.

Grant Williams: C

Williams had a solid season but never really established a consistent role. There were several stretches in which he slipped out of the rotation completely.

He is a strong, sturdy defender who had a good grasp of the Celtics’ scheme, and some of Williams’s finest moments came when he was used as a small-ball center. But the presence of Robert Williams, Thompson, and Theis limited his opportunities in the post.

On offense, he raised his 3-point percentage from 25.0 to 37.2, but his shooting numbers dipped significantly after the All-Star break and he shot just 58.8 percent from the foul line for the season.