Pro football commissioner Pete Rozelle has issued statements to club presidents deploring "unnecessary violence" and threatening serious discipline up to and including multigame suspensions, it was learned yesterday.

In copies of a memorandum and accompanying commissioner's statement obtained by The Washington Post, Rozelle makes it obvious he is taking a forceful stand following two recent court cases and in view of a rematch Sept. 25 between the Oakland Raiders and the Pittsburgh Steelers, whose game last season precipitated one of the suits.

Flagrant personal fouls are clearly outside the rules," the statement read, "and are calculated either to disable opposing players or to 'intimidate' them into less effective performance.

"They often entail an entirely unreasonable risk of unnecessary injury to opposing players, and potentially unfortunate consequences to the victim's teammates and coaches as well. They do not belong in professional football, and will not be tolated by this office.

"If there is to be 'intimidation' on the playing field, it must result from superior performance within the rules - not from calculated or unbridled violence.

"Accordingly, all players, coaches and clubs are reminded that unnecessary violence outside the rules of the game will be cause of serious league discipline up to and including multigame suspension, whether or not it is detected by the game officials."

The "whether or not" was underlined by the commissioner's office, and as if to make cleare what he meant by "violence," Rozelle headed his statement with a definition.

"'Violence'," the statement began, "as Webster defines it and as the public perceives it, is conduct characterized by 'extreme and sudden ... unjust or improper force.' It has no proper place in professional football."

In the memorandum to the club presidents, the commissioner ordered, "Copies of the enclosed statement are A21, Col. 1> to be personally distributed to each player and to each member of your coaching staff."

Coach Chuck Noll of the Steelers called safety George Atkinson of the Raiders "part of the criminal element in pro football" after a game in 1976 when Atkinson knocked out wide receiver Lynn Swann of the Steelers with a forearm blow to the back of the head.

Atkinson sued Noll for $2 million, charging slander in a federal court in San Francisco. The case was dismissed, but Noll admitted during his testimony that some players on the Pittsburgh club also could be called part of the "criminal element."

Noll named All-Pro cornerback Mel Blount, defensive tackles Joe Greene and Ernie Holmes and safety Glen Edwards.

An upshot was that Blount said he resented the charge to the extent that he sued Noll for $5 million in a case that is pending. Blount has not reported to the club this season.

Previously, Blount sought to renegotiate his contract without success and asked to be traded.

Atkinson contented in his suit that Rozelle was blased in favor of the "establishment" Steelers. The managing general partner of the Raiders is Al Davis, who joined a year ago with owner Carroll Rosenbloom of the Los Angeles Rams in trying unsuccessfully to curb the commissioner's authority. Rosenbloom later reconciled his dispute with Rozelle.

Davis was commissionenr of the American Football League when it voted to merge with the National Football League. Davis lost that position and joined the Raiders.

After the Atkinson-Noll trial, a federal judge in Denver dismissed a $1 million suit by Denver Broncos safety Dale Hackbart against running back Booble Clark of the Cincinnati Bengals. Hackbart charged that he suffered a neck injury in 1973 becouse of "outrageous conduct" by Clark.

Hackbart contended that Clark delivered a forearm blow to the back of his (Hackbart's) head while thay jousted on a pass play in the end zone.

The judge ruled that "civil courts cannot be expected to control the violence in pro football."