Williamson was listed as questionable heading into Thursday's matchup with a sprained right thumb. He injured the thumb on Monday against the Boston Celtics but isn't expected to be out for an extended period of time.
The 20-year-old dealt with injuries throughout his rookie season in New Orleans, as he played in only 24 games a season ago. He has only missed two this season -- one game in January because of an inconclusive COVID-19 test and another game because of a toe injury just before the All-Star break.
Ball, who was also listed as questionable, will miss his sixth consecutive game with a right hip flexor strain.
Ingram, a late addition to the injury report, was ruled out with right first MTP irritation. The first MTP -- the first metatarsophalangeal joint -- is the big toe joint.
Williamson (26.4 points per game), Ingram (23.8 PPG) and Ball (14.2 PPG) have been the Pelicans' top three scorers this season.
Entering Thursday's game, New Orleans had won four of their past five games and six of their past nine in their push for the Western Conference playoffs.