KNOXVILLE, Tenn. -- Tennessee defensive tackle Danny O'Brien has been suspended for what Volunteers coach Butch Jones described as a violation of team rules and policies.

Jones said Wednesday that O'Brien would miss Saturday's game against No. 19 Oklahoma (1-0) and no timetable is set for the junior's return. Jones didn't specify the nature of O'Brien's violation.

"I don't want to sit here and tell you it's one game," Jones said. "I don't want to sit here and tell you it's six games. It's going to be the ebb and flow, and it could be ever-changing."

Tennessee lineman Danny O'Brien, who started 12 games last season, had a sack in the opener but will be suspended for at least Saturday's game against Oklahoma for violating team rules. Bryan Lynn/Icon Sportswire

No. 23 Tennessee (1-0) also will be missing reserve safety Max Arnold and reserve running back Ralph David Abernathy IV this week. Jones said Arnold has a sprained medial collateral ligament and Abernathy has a sprained ankle.

Tennessee did get some good news. Senior safety LaDarrell McNeil, who was fourth on the team with 76 tackles last season, is expected to play Sept. 19 when the Vols host Western Carolina. Jones said last week there was only a slight chance McNeil would play at all this season due to "neck instability."

Jones said Wednesday that McNeil visited doctors in his home state of Texas, where he went through a round of tests and was cleared to return to practice. McNeil has 31 career starts.

"Just seeing the smile on his face and the excitement of his teammates was very, very rewarding," Jones said.

O'Brien, who is from Flint, Michigan, had two tackles and a sack last week while making his 12th career start in a 59-20 victory over Bowling Green. O'Brien started 11 games last season and had 21 tackles, including 4 1/2 for loss.

O'Brien's suspension likely means that junior Kendal Vickers and senior Owen Williams will be Tennessee's starting defensive tackles against Oklahoma. Jones said freshman defensive tackles Shy Tuttle and Kahlil McKenzie likely would get more playing time as well.

This marks the second straight game in which Tennessee has had a player suspended.

Senior receiver Alton "Pig" Howard, who led the Vols in catches (54) and yards receiving (618) last season, missed the Bowling Green game due to a violation of team rules. Howard is expected to play against Oklahoma.

"We have standards and expectations, and we're never going to compromise those," Jones said.