KISSIMMEE, Fla. — As the Philadelphia 76ers gear up for the start of the playoffs, Ben Simmons will depart the NBA bubble to have left knee surgery.

The 24-year-old guard, who was selected to the all-star team in both of the past two seasons, injured his left kneecap during his third bubble game, a 107-98 win over the Washington Wizards on Wednesday. After evaluating treatment options, the 76ers opted for surgery to address a loose body in the knee. ESPN first reported the decision.

Simmons’s return timeline is unknown, but he has not yet been ruled out for the remainder of the season. Once a player leaves the bubble, he must undergo a quarantine period upon his return.

Philadelphia entered the season as one of the favorites to win the Eastern Conference, but an inconsistent season plagued by lineup fit issues and road woes has left the 76ers (42-27) as the conference’s sixth seed entering Sunday’s action. Despite the loss of Simmons, Philadelphia is 3-1 in the bubble with the playoffs set to begin Aug. 17.

Simmons, who signed a five-year, $170 million maximum contract extension last summer, averaged 16.4 points, 7.8 rebounds and 8.0 assists in 57 appearances this season and solidified his reputation as one of the league’s most versatile defenders. While his long-standing shooting struggles persisted, Simmons did hit his first career three-pointer in November.

Before the league’s shutdown in March, he missed 10 games while dealing with back problems. Despite the injury, Simmons opted to rehab during the hiatus and return to play in the bubble.

“He really has worked physically to come back stronger,” Coach Brett Brown said. “I feel bad for him that this situation has happened after all the hard work he put in.”

The loss of Simmons from the lineup should open a greater role for big man Al Horford, who was moved to the bench when bubble play began as the 76ers searched for better spacing. Horford returned to the starting lineup Friday following Simmons’s injury.

Shake Milton should continue to start at point guard and function as a lead playmaker. Reserve guard Alec Burks could also be called on to fill in the gaps as an offense initiator.

Philadelphia faces significant pressure to win in this postseason, given preseason expectations and its costly, veteran-dominated roster. If the 76ers fall short in the first round, the front office could move on from Brown or look to shake up its star core.

“You’re just numb to it,” Brown said, citing the numerous injury issues the team has faced this season. “You coach who you have. I do genuinely believe that this can galvanize our group and bring us, in an inverted way, together.”

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