Philadelphia’s Joel Embiid had played in 63 games this season, exceeding some expectations. (AP Photo/Matt Slocum)

When Joel Embiid said on social media Wednesday while being treated at a hospital that his situation was “Not good,” the 76ers star turned out to be painfully accurate. Initially thought to have escaped serious injury after accidentally butting heads with teammate Markelle Fultz during a game, Embiid was announced Thursday by Philadelphia as having suffered a concussion and a fractured eye socket, surgery for which could jeopardize his availability for Philadelphia’s first-round playoff series.

League sources confirmed to The Post’s Tim Bontemps that the surgery is expected to keep Embiid out of action for two to four weeks, and the NBA’s postseason starts on April 14. On Sunday, the 76ers clinched their first playoff berth since 2012, and their surprisingly successful season has been fueled by Embiid’s strong play.

Arguably the biggest surprise about Philadelphia (44-30) has been Embiid’s availability for 63 games, given that he missed his first two NBA seasons entirely with foot injuries and his rookie campaign last season was limited to just 31 games, ending early because of knee issues. The 24-year-old is averaging 22.9 points, 11.0 rebounds, 3.2 assists and 1.8 blocks this season, earning his first all-star nod and defensive player of the year consideration.

Ben Simmons, a leading rookie of the year candidate, has also been a standout for the 76ers, and the team has gotten solid contributions from Dario Saric, J.J. Redick and Robert Covington, its other regular starters, but Embiid has been the difference-maker. As Sports Illustrated’s Ben Golliver noted, with Embiid on the floor, Philadelphia has had the league’s best defensive rating and fourth-best offensive rating, numbers that plunge to 14th and 27th without him.

The 76ers said that Embiid was evaluated Wednesday for a concussion and found “asymptomatic,” but he “later began experiencing symptoms,” and has been placed in the NBA’s concussion protocol. A CT scan revealed the fracture of his left orbital bone, and the team said that his surgery “will be performed in the coming days.”

The incident occurred in the second quarter of a 118-101 home win over the Knicks, while Embiid was trying to complete a dribble handoff to Fultz near the three-point line. Embiid lost control of the ball and both players made a move for it, resulting in Fultz’s head smacking into his teammate’s face.

Embiid lay on the court for several minutes, holding his face, before being helped off the court and escorted to the locker room, where, according to the 76ers, he “passed the NBA’s locker room concussion assessment tool.” He was ruled out for the rest of the game, though, and taken to a hospital, where more testing took place and revealed a much more concerning situation than the initial diagnosis of a “facial contusion.”

“My heart dropped,” Fultz said Wednesday of his collision with Embiid. “He’s a tough guy. All I can do is pray for him.”

Fultz was playing in only his second game back from a 68-game absence, one caused by a shoulder injury and prolonged by his struggles to regain his shooting form and confidence. 76ers fans did not have long to revel in the return of last year’s No. 1 overall pick before he inadvertently caused a major problem for the team’s most important player.

While Fultz tries to use the final eight games of the regular season to get up to speed before the postseason, his team is left to hope that Embiid can return on the shorter end of his recovery timeline. The 76ers began Thursday in fourth place in the East, a half-game behind the Cavaliers for third and half-game in front of the Pacers for fifth, with the Wizards in sixth.

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