The Philadelphia 76ers guard suffered the injury in Wednesday's NBA clash against Washington Wizards and the team have said they are unsure about how long he'll be out of action.

Asked if the Newcastle Hunters junior would miss the rest of the season, Philadelphia coach Brett Brown said, "Some of the information is fluid. It's just that the stuff is still being evaluated."

Philadelphia and Boomers coach Brown said the 24-year-old Simmons is feeling anxiety over the situation.

"There is clearly disappointment," Brown told reporters.

"I don't know if anyone really understood what he did to get ready to play basketball again (after a 2016 foot injury). He really invested time.

"It's monotonous, some of the smaller things he had to do. ... I think the uncertainty of what really is it right now is obviously there.

"But he's a great teammate, and his teammates care about him."

The two-time All-Star got hurt midway through the third quarter.

He was shown walking gingerly as he exited the arena shortly before the end of Philadelphia's 107-98 triumph at the ESPN Wide World of Sports Complex near Orlando.

Simmons sustained the injury either while grabbing a rebound, he dribbled slowly up the floor and passed the ball to teammate Al Horford.

After a whistle stopped play with 5:46 remaining, Simmons began touching his knee and walked off the court and continued to the locker room.

Simmons had eight points, six rebounds and four assists in 23 minutes on Wednesday.

He is averaging 16.4 points, 8.0 assists and 7.8 rebounds in 57 games this season.

While you're with us, did you know the Newcastle Herald offers breaking news alerts, daily email newsletters and more? Keep up to date with all the local news - sign up here

IN THE NEWS: