Kansas announced the suspension Wednesday in a statement from coach Bill Self.
The school did not reveal a specific length of De Sousa's suspension or additional punishment for any other player, citing its joint review with the Big 12.
"I have suspended Silvio De Sousa indefinitely pending the final outcome of the review by KU and the Big 12 Conference," Self said in his statement. "As I said last night, we are disappointed in his actions and there is no place in the game for that behavior."
The melee began when De Sousa blocked DaJuan Gordon's shot in the final seconds of an 81-60 victory and then stood over Gordon. At one point during the brawl, De Sousa, who had thrown multiple punches, held a stool above his head before assistant coach Jerrance Howard grabbed it from him.
"The players told me they went on the court because they thought the game was over," Kansas State coach Bruce Weber said on Wednesday's Big 12 media teleconference.
Weber said he was "sad" about the events that unfolded and added that he expected the Big 12, in consultation with leaders from both schools, to announce suspensions "sooner rather than later."
Self said Tuesday night that the fight was "not part of heated competition." He added that he had been in contact with a woman who was caught in the middle of the fight and said he planned to check on her on Wednesday.
"I'm sure we'll correspond with her today, see how she's feeling today," Self said.
The Associated Press contributed to this report.