Ben Simmons is out indefinitely after suffering a subluxation of the left patella in the Philadelphia 76ers' 107-98 win over the Washington Wizards on Wednesday.
A subluxation is a partial and temporary dislocation, and similar injuries reportedly require a recovery period of several weeks.
"This one stings for sure," Philadelphia coach Brett Brown said on Thursday. "We all felt like, with the pandemic and are we going to play again, it obviously bought time for Ben.
"In relation to sort of being incredibly down about it, I'm not. I feel numb to it."
Simmons was injured in the third quarter against the Wizards, appearing to tweak his knee after grabbing his sixth rebound of the game. At the next stoppage of play, he limped straight to the locker room.
He is now looking at treatment options, and Brown expects the team will be able to put a timeline on his rehab by Friday.
"Some of the information is fluid, it's still moving," Brown said. "In relation to saying any type of deadline, timeline, playoff, whatever, I'm not in a position to offer anything. Not because we don't want to, but stuff is still being evaluated.
"What I do know — it's boring, but we play Orlando [Magic] tomorrow and we don't have him. That's kind of all I know at this point."
In his third full season in the NBA in 2019-20, the 24-year-old Simmons made his second All-Star team, averaging 16.4 points, 8.0 assists and 7.8 rebounds in 57 games. The 76ers went 35-22 with Simmons in the lineup, and 6-5 in games he did not play.
"Ben is an incredible player, an incredible athlete," Sixers point guard Shake Milton said. "A superhuman. So hopefully he's able to heal superfast and get back out on the court, because we need him."
Philadelphia have already clinched a playoff berth and entered Thursday's play a game back of the Indiana Pacers for the Eastern Conference's fifth seed.