Joe Thomas, who built Minnesota, Miami and Baltimore into National Football League powerhouses, was fired today as general manager of the San Francisco 49ers, who finished with the worst record in pro football this season.

"I have not been satisfied with our total operation," Edward DeBartolo Jr., owner of the 49ers, said in an announcement.

DeBartolo also said the coaching staff, led by Fred O'Connor, would not return next season.

It was reported last week that Stanford Coach Bill Walsh has agreed to take the reins of the 2-14 49ers. Shortly after DeBartolo's announcement, Stanford Athletic Director Andy Geiger called a press conference for Tuesday "concerning the school's head football coaching position. We have no other comment at this time." Reportedly, Walsh has been released from his contract with the university.

It also has been reported that Don Klosterman, general manager of the Los Angeles Rams, may replace Thomas. Also mentioned has been Dick Mansperger, player personnel director of the Seattle Seahawks.

Thomas, 56, traded away many of the 49ers' key players as he tried to rebuild an ineffective club with new and young talent.

However, he came under intense criticism for trading running back Delvin Williams to the Dolphins and giving up on veteran quarterback Jim Plunkett. The offense was left in the hands of second-year quarterback Steve DeBerg and Scott Bull, who had seen little action.

Thomas was hired in 1977. His most noticeable acquisition was O. J. Simpson before last season began. But the star running back injured a shoulder at midseason and never returned to the lineup.

Simpson's injury was only one of several to plague the 49ers. Also lost for the season with a knee injury was Wilbur Jackson, another outstanding running back. In the last game of the season, wide receiver Freddie Solomon and defensive back Bruce Threadgill were pressed into service as quarterbacks after DeBerg and Bull were injured.

Football insiders have been predicting DeBartolo would fire Thomas, hire Walsh, then select a new general manager.

"I feel we must make changes to become more competitive," DeBartolo said. "Certainly I am distressed that we have been losing games -- everyone connected with the organization shares that feeling, and I am sure that our fans do.

"What concerns me every bit as much as our record is the fact that our image and stature in the community has suffered -- and not entirely due to wins and losses."

O'Connor was named an interim coach by Thomas in the middle of the season. He succeeded Pete McCulley, former Redskin assistant who posted a 1-8 record. O'Connor's assistants, all of whom were hired by McCulley, were Frank Gansz, Earl Leggett, Dan Radakovich, Floyd Reese and Les Steckel.

DeBartolo said he would make an announcement soon -- some sources said this week -- about the remainder of the 49er organization.

Neither Thomas nor O'Connor was immediately available for comment.

Walsh, who directed Stanford to an 8-4 record last season and previously spent 10 years as an NFL assistant coach, refused to comment when reached after DeBartolo's announcement.