ATLANTA, GEORGIA - JANUARY 17: Head coach Joe Mazzulla of the Boston Celtics reacts against the Atlanta Hawks during the fourth quarter at State Farm Arena on January 17, 2026 in Atlanta, Georgia.

The Boston Celtics were hit with some tough news going into Game 7 against the Philadelphia 76ers on Saturday night.

Although the head coach Joe Mazzulla claimed that Tatum was a sure thing to play on Saturday, the plans shifted when Tatum came to the team with some concerns about his knee.

GettyJayson Tatum #0 of the Boston Celtics controls the ball against Paul George #8 of the Philadelphia 76ers in the first quarter during game three of the Eastern Conference first round playoffs at Xfinity Mobile Arena on April 24, 2026 in Philadelphia, Pennsylvania.

Before Game 7, Joe Mazzulla explained that Tatum’s injury was “back of the knee stiffness.” If the Celtics survive Game 7, he’ll be considered day-to-day.

But for now, the Celtics have to focus on taking out the Sixers on Saturday. With Tatum’s absence placing the Celtics in an unexpected spot, Mazzulla is rolling with a shocking lineup for the game.

Boston Celtics Announce Shocking Lineup vs 76ers

GettyBOSTON, MASSACHUSETTS – MARCH 25: Jaylen Brown #7 of the Boston Celtics laughs during the second half at TD Garden on March 25, 2026 in Boston, Massachusetts. The Celtics defeat the Thunder 119-109. NOTE TO USER: User expressly acknowledges and agrees that, by downloading and/or using this Photograph, user is consenting to the terms and conditions of the Getty Images License Agreement. (Photo by Maddie Meyer/Getty Images)

The Celtics are starting Derrick White, Jaylen Brown, Ron Harper Jr., Luka Garza, and Baylor Scheierman.

Three of the five players starting have never started a playoff game.

Garza is a well-known G League standout who joined the Celtics for the first time this year after a run with the Minnesota Timberwolves. Although Garza has appeared in 69 games for the Celtics this season, he started just six of those matchups.

GettyBOSTON, MASSACHUSETTS – JANUARY 21: Micah Potter #11 of the Indiana Pacers looks on as Luka Garza #52 of the Boston Celtics guards him during the second half at TD Garden on January 21, 2026 in Boston, Massachusetts. NOTE TO USER: User expressly acknowledges and agrees that, by downloading and or using this photograph, User is consenting to the terms and conditions of the Getty Images License Agreement. (Photo by China Wong/Getty Images)

As for Harper, he’s a former undrafted prospect out of Rutgers. Similar to Garza, Harper has had plenty of runs in the G League. Before getting to the Celtics this season, Harper had just 11 appearances in the NBA. This year, he appeared in 29 games for the Celtics, starting three times. Harper averaged 11.0 minutes on the court.

Baylor Scheierman might be getting his first playoff start, but he was a key role player for Boston throughout the year. In 77 games, Scheierman picked up 20 starts and averaged 18.6 minutes on the court. He produced 5.5 points per game, while shooting 39.9% from three.

The Sixers and the Celtics are slated for a 7:30 PM ET tip.