The Boston Celtics’ newest two-way contract addition, guard Devin Carter, will miss the start of the 2026-27 regular season after being diagnosed with mononucleosis.
Carter, signed Saturday, is out for Tuesday’s season opener against the Detroit Pistons and has no firm return timeline, according to reports citing Boston Globe writer Gary Washburn. Washburn said Carter could miss a few more weeks.
The 24-year-old appeared in just one of Boston’s four preseason games. He scored 17 points on 5-of-9 shooting, grabbed five rebounds, dished three assists and recorded two steals in 25 minutes during an Oct. 8 win over the Cleveland Cavaliers before the illness sidelined him.
Celtics coach Joe Mazzulla addressed the decision to retain Carter after practice Sunday.
“He’s very talented,” Mazzulla said. “He’s done some good things in the league. But with us, he’s put his head down, (and was) really impactful on the defensive end of the floor in the Cleveland game.”
Mazzulla added that Carter “did some things for us offensively, but I think we have a guy who came in with a great attitude, (and) did what we asked him to do.” He noted, “You see the talent and the impact that he could have. You want to be able to invest in that.”
Carter was the No. 13 overall pick by the Sacramento Kings in the 2024 NBA Draft out of Providence. He played high school basketball in New Hampshire after growing up in Florida and also attended South Carolina.
Across 74 games with the Kings, including 12 starts, Carter averaged 6.4 points, 2.7 rebounds and 1.9 assists in 14.8 minutes per game. Last season he appeared in 38 games and posted 8.9 points, 3.3 rebounds and 2.7 assists while shooting 41.4% from the field and 26.3% from 3-point range.
The Kings traded him to the Atlanta Hawks in June. Atlanta waived him in September, clearing the way for Boston to bring him in on an Exhibit 10 deal that was later converted.
As a two-way player, Carter can appear in up to 50 regular-season games with the Celtics and will also be eligible for the Maine Celtics in the G League. Maine’s season opens Nov. 6 against Westchester, giving him additional time to recover.
Carter is the only player listed on Boston’s injury report for the opener. Stars including Jayson Tatum, Paul George, Derrick White, Payton Pritchard and Mitchell Robinson are available, according to reports.
Detroit finished as the East’s top seed last season. Boston went 56-26 and earned the No. 2 seed.
The mononucleosis diagnosis explains Carter’s absence from the final three preseason contests. He remains away from the team while recovering.
Boston converted his deal despite the limited on-court sample, prioritizing the upside shown in that single preseason outing and during camp.
Carter joins Dillon Mitchell and Amari Williams on two-way contracts. The Celtics enter the season with an open standard roster spot, remaining under the luxury tax line.
