The 76ers will miss Joel Embiid on several fronts. On offense, his 23.4 points a game creates a void, but his absence on defense is where the Sixers will be missing him the most.

Embiid had surgery on Friday afternoon in New York for a torn radial collateral ligament in the ring finger of his left hand, an injury he suffered Monday in a 120-113 victory over the visiting Oklahoma City Thunder.

He will be reevaluated in one to two weeks, but sports medicine specialists say the procedure typically requires a month of healing followed by several weeks of physical therapy.

Al Horford, who moved from starting power forward to center to replace Embiid in Thursday’s 109-98 win over the Boston Celtics, talked afterward of Embiid’s presence on the defensive end.

“Really, it is just the fact that as defenders on the perimeter we get spoiled a little bit because if anything, we can send it to Joel and teams are going to struggle,” Horford said. “When he is not around, we have to be on edge and [make sure we] don’t get beat off the dribble and you have to be there.”

Embiid is third in the league in rebounding percentage (34.4%), according to basketball-reference.com. That is the estimate of available defensive rebounds that a player grabs while he is on the floor. He is ninth in the NBA in defensive rating (101.6), an estimate of points allowed per 100 possessions. Embiid is 13th in defensive win shares (1.9), an estimate of the number of wins a player contributes because of his defense. Teammate Ben Simmons is fifth at 2.3.

The statistics don’t always do Embiid justice. His presence on the court gives the Sixers confidence that they can gamble on defense and he can pick up for their mistakes.

“We don’t have that rim protector like Joel is,” said Horford, who had 17 points (on 7-for-11 shooting), eight rebounds, six assists, and a game-best plus-19 rating against the Celtics. “We have to get creative, and that is what we did [Thursday night] and found a way.”

Still, without Embiid, the Sixers blocked five shots, compared to one for Boston, had a 50-38 edge in points in the paint, and outrebounded Boston, 48-38.

The immediate challenge is to keep the momentum going on a two-game road trip: Saturday in Dallas and Monday in Indiana.

The Sixers (25-14), who had off from practice on Friday, are 4-4 in games without Embiid this season. Even with Embiid, the Sixers lost, 117-98, to Dallas on Dec. 20. The Mavericks (23-14), who played without then-injured Luka Doncic, outscored the Sixers, 48-38, in the paint.