The Sixers announced (via Mark Medina of USA Today) that Richardson has a concussion and will start the league's recovery protocol on Monday after leaving Sunday's game with against the Los Angeles Clippers.
Richardson already missed a chunk of time after straining his left hamstring during a Jan. 22 loss to the Toronto Raptors.
The 76ers haven't dealt with a high volume of injuries this season, but when players have gotten hurt, it's led to extended absences. Joel Embiid has suffered several injuries during the season, while Ben Simmons is out until at least mid-March with a lower back injury.
Roster depth isn't a strength for the Sixers, so losing any starter right now is a problem for head coach Brett Brown as his team trails the Toronto Raptors and Boston Celtics in the Atlantic Division and sits at No. 5 overall in the Eastern Conference.
Richardson ranks fourth on the team with 14 points per game. He hasn't been as effective from three-point range (32.2 percent) compared to the rest of his career (36.1), but his ability to score makes him an asset for a Sixers squad that lacks players capable of consistently creating their own shots.
Until Richardson is able to get back on the court, Brown will likely go with Furkan Korkmaz in his starting lineup.