Next man up, the 76ers said.

That was the theme heading into their 109-98 victory over the Boston Celtics on Thursday night at the Wells Fargo Center. The Sixers were without franchise player Joel Embiid, who will have surgery Friday in New York to repair a torn ligament in his left ring finger. He will be evaluated in one to two weeks.

“Next-man-up mentality,” Tobias Harris said before the game. “There is not much thinking to it. This is what we have all been able to do our whole life, play this game, so just be ready to go.”

That mentality enabled the Sixers to come from behind against their Atlantic Division rival. The Celtics led by as many as 15 points in the second quarter.

The victory improved the Sixers to 25-14 and was their second straight home win after losing four straight on the road. They also improved to 3-0 this season against the Celtics (25-11). The teams will play their fourth and final regular-season matchup on Feb. 1 in Boston.

Al Horford started at center in place of Embiid. Mike Scott started in place of Horford at power forward. They were joined by normal starters Harris, Josh Richardson, and Ben Simmons.

Simmons moved to center when Horford first went to the bench. Two-way player Norvel Pelle was the other reserve center. The three players made the most of their opportunities on a night when Richardson finished with a game-high 29 points.

Horford, who played center the last three seasons in Boston, finished with 17 points on 7-for-11 shooting -- including making 2 of 3 three-pointers. The 13th-year veteran and five-time All-Star also added eight rebounds, six assists, two blocks, and a steal.

Horford was asked if he thought there would be a stretch in which he would have to play center when he signed with the Sixers.

“I think coming here I expected to play a little more of the four,” Horford said. "I also know that one of my strengths as a player is to be able to play inside and play outside, play the four play the five, guard different positions on the court.

“Yes. I was expecting that. I feel wherever I am needed, that is one of the strengths I bring to the team that I am able to do different things.”

Pelle had six points on 3-for-3 shooting to go with four rebounds and two blocks in 12 minutes, 38 seconds. He has only five days left toward the maximum number of days (45) an NBA team is allowed to bring up a player on a two-way contract.

After that, teams have to sign the player to the regular 15-man roster or send him to the G League. In Pelle’s case, the plan was for the team to sign him to the 15-man roster after 45 days or part ways with the big man.

On Friday, the 26-year-old received a standing ovation from the sellout crowd of 20,822 when he left the game for good with 9 minutes, 5 seconds remaining.

“Oh my goodness. I love Philly for that,” Pelle said. “I love that. I really did.”

The California native feels that he has a connection to the city because of his blue-collar style of play and all the hard work he has put in to get this stage of his career.

“Philly’s known for just being hard-nosed and just get the job done,” he said. “Don’t cry about it. I feel like I can dictate that once I’m on the court.”

Simmons had 19 points, 9 rebounds, 3 assists, and 1 steal. Harris was the other double-figure scorer with 16 points.

Kemba Walker paced the Celtics with 26 points. Marcus Smart added 24 points in a reserve role.

The Sixers improved to 18-2 at home.