Coach Jim Mora ended practice early after an altercation involving wide receiver Devin Lucien escalated, ending with receiver Shaquelle Evans and defensive back Anthony Jefferson needing to be separated.
Mora had the team run for 10 minutes, chewed out those involved in the altercation and lectured the team. He ordered players to huddle and left the field with most of his staff.
Mora returned later to address the situation with the media.
"Practice was going really good, the intensity was high, then…," Mora said, pausing.
"As you know, I don't like fights. I decided to stop practice and run them. They had a team meeting and we'll come back at it tomorrow."
The 11-on-11 scrimmage started well, with quarterback Brett Hundley throwing a 68-yard touchdown pass to Evans.
Afterward, Hundley said, "As a team right now we've got to figure what we're going to do." Hundley was cut short by a UCLA media relations staff member, who said Hundley would not answer questions about the fight.
The altercation happened immediately after Mora had players remove their shoulder pads, intending to dial back the contact after four offensive linemen left because of injuries.
Lucien became heated after a play and things escalated. Evans came in from the sideline and wrestled with Jefferson, though no punches were thrown.
"The intensity gets ramped up," Mora said. "What is really important is we have to maintain our composure and know when to back off.... The two guys in the fight were skill position players. All it takes is for one of those guys to break a finger and we've got problems."
Mora said he was intending to end practice early anyway. No players would face disciplinary action, he said.
"In football, stuff happens, but you just can't let it go," Mora said. "Some coaches say they like that. I don't."
Another day passed with UCLA freshman defensive end Eddie Vanderdoes limited to individual work on the side.
Vanderdoes was expected to contribute at left defensive end, where the Bruins have a serious need. But he has been unable to participate in team drills because of a sore back.
He underwent an X-ray on Sunday and Mora said, "We're waiting for them to read it." He added, "Eddie felt a lot better today."
Mora said that things are reaching a tipping point, with the season opener against Nevada less than three weeks away.
"You can't replace the reps that he is missing right now," Mora said. "Every day he doesn't practice, it bothers me.... He's capable of contributing if he gets the practice time."
Mora saw how injury delayed nose tackle Ellis McCarthy a year ago during training. McCarthy had minor knee surgery and was unable to make an impact during the season.
"Ask all the frosh, to a man, none have ever expected it to be this fast," Mora said. "They never expected it to be this intense. They never expected the players to be this big and physical. Eddie hasn't gotten a taste of that yet."
Linemen Caleb Benenoch, Alex Redman Redmond, Ben Wysocki and John Lopez left practice. Benenoch had "tightness" in his chest, Mora said. Redmond, Wysocki and Lopez took hits to the head.... Defensive end Ian Taubler, tackle Poasi Moala and guard Kevin McReynolds have suffered concussions and have been sent back to Los Angeles to be evaluated. Taubler is not expected to return to San Bernardino for training camp.... Defensive end Cassius Marsh sat out because of a sore knee.