Celtics rule out important reserve for matchup vs. Wizards

The Celtics will be without one of their top reserves when they visit the Washington Wizards on Thursday night.

Boston ruled backup wing Sam Hauser out for its game at Capital One Arena due to lower back pain. Hauser was added to the Celtics’ injury report Wednesday and was listed as questionable.

Hauser played 24 minutes off the bench in Tuesday night’s season-opening rout of the New York Knicks, shooting 4-for-10 from the field and 2-for-7 from 3-point range. He finished with 10 points, five rebounds and one assist in the 132-109 victory at TD Garden.

This will be just the sixth game Hauser — who signed a four-year, $45 million contract extension in July — has missed since the start of the 2022-23 season. The 26-year-old made 79 appearances last season, including 13 starts, and was one of the NBA’s most effective 3-point threats (42.4% on 5.9 attempts per game).

With Hauser unavailable, the next man up against Washington could be second-year pro Jordan Walsh, who impressed this preseason after spending most of his rookie year in the G League. Walsh saw substantial action with the Celtics’ rotation players in four of their five exhibition games and looked far more comfortable than he did last season or at the Las Vegas Summer League.

When Hauser and starting guard Jrue Holiday both sat out Boston’s preseason finale, Walsh was one of the first players off the bench and played 24 minutes.

“Just having an understanding of what his job is: defend at a high level, defend multiple positions, rebound and then make reads on the offensive end,” head coach Joe Mazzulla said after Walsh notched a 16-point, 10-rebound double-double earlier in the preseason. “He’s doing a great job. Just really proud of his growth.”

Walsh, the youngest player on the Celtics’ roster, was not part of Mazzulla’s primary rotation against the Knicks, only playing the final six garbage-time minutes. The 20-year-old saw action in just nine NBA games last season.

Thursday’s contest is the season opener for the Wizards, who are coming off a dismal 15-win season and boast one of the NBA’s weakest rosters.