ALAMEDA, Calif. -- A week and a day after a heated and spirited OTA practice that featured at least three skirmishes between players, the Oakland Raiders turned the volume down a bit on Wednesday.

The Raiders worked out without helmets, as opposed to last week’s helmeted practice, and, as coach Jack Del Rio might put it, took better care of each other with more of a mental day on the field.

“We have to learn how to practice in shorts and, sometimes, with taking the helmets off and lightening it up,” Del Rio said. “We have to be the team that understands what it looks like to maintain that mental intensity and back it down physically. We’ll do that in training camp.

“It’s an opportunity for us to help them understands what it looks like.”

It was practice No. 9 of 10 before next week’s mandatory three-day minicamp.

Players who were not seen on Wednesday: running back Roy Helu Jr., receivers Nathan Palmer and Jaydon Mickens, defensive linemen Denico Autry and Mario Edwards Jr., who had been on the field for the stretching period in the first two open OTA sessions, linebacker Neiron Ball and defensive backs Dexter McDonald, Reggie Nelson, Neiko Thorpe and first-round draft pick Karl Joseph, who is expected to be ready for training camp.