Coach Tom Landry has picked his Dallas Cowboys to finish fourth in the National Football Conference East and says he will name Danny White as his starting quarterback. His pick to win the NFC East? The Washington Redskins.

Landry said Dallas will trail Washington, St. Louis and New York. "Washington got (George) Rogers, and they have confidence in him and (John) Riggins," he said. "Everybody can start picking dark horses to knock off the champion, but you better stick with the champion until he proves he's not the champion anymore."

Landry said he favors White, 33, over Gary Hogeboom, 26, because he detects a difference in the way White is perceived by teammates. Landry said, "He's got the ball. He is going to play until he proves he can't do the job the way I want him to." . . .

Pledging to bring to the broadcasts "my personality, my good humor, my good looks," Joe Namath will replace Don Meredith on the announcing team for "Monday Night Football," Roone Arledge, president of ABC News and Sports, announced. Frank Gifford, who has been with the show since its second year, and O.J. Simpson, who moved into the booth last season, will complete the broadcast crew.

Namath, the former New York Jets quarterback who led them to the Super Bowl championship in 1969, signed a five-year contract, although ABC has two years left in its agreement with the NFL. Arledge said the network anticipates continuing its relationship with the NFL and that Namath might do some movie work for the network as well . . .

New Jersey Generals running back Herschel Walker, who broke professional football's single-season rushing record, was named the U.S. Football League's most valuable player. The Professional Football Writers of America selected Walker for his 2,411-yard rushing season, which broke the mark of the Los Angeles Rams' Eric Dickerson. He gained 2,105 yards in the National Football League last season.