They are the only team in the NFL that had a winning offseason. Now, it seems, Al Davis and his Raiders will develop their judicially sponsored "pursuit of happiness" in Los Angeles.

In 1981, there was little happiness for the 7-9 Raiders, who met shutout (an NFL-record three straight) and scorn during their first losing season since 1964. Jim Plunkett hurt his thumb, then gave way to Marc Wilson, who completed just 47 percent of his passes. Bob Chandler, Mark Van Eeghen, Reggie Kinlaw and Mike Davis all were hurt.

This is a team of experience, however. It has added top draft pick Marcus Allen, the Heisman running back from USC, defensive end Lyle Alzado and running back Greg Pruitt. They may not come back to Oakland, but these Raiders will come back.

They will confront division champion San Diego (10-6), the team whose defense usually is so bad it negates its superb offense. Sure, the Chargers still have Dan Fouts (33 touchdowns, 17 interceptions), Kellen Winslow (88 catches), Charlie Joiner (70 catches) and Wes Chandler (69 catches). Now, if only the defense could stop somebody.

Defensive coordinator Jack Pardee has moved into the oil business. Tom Bass enters from Tampa Bay, as do linebackers Dewey Selmon and David Lewis. Safety Tim Fox (New England) is another veteran who has come in to help a team that allowed 269.4 passing yards per game and whose first 1982 pick didn't come until the seventh round.

For Denver (10-6), Craig Morton, now 39, still ranks over Steve DeBerg and Mark Herrmann on the depth charts. Gerald Willhite, the rookie running back from San Jose State, should help Rick Parros (749 yards) nudge the running game above the 3.7-yards-per-carry mark, which ranked fourth worst in the AFC in 1981.

Randy Gradishar, Bob Swenson and Tom Jackson have been joined by Robert L. Jackson (Cleveland) on the Denver defense. They won't take Denver a mile high, but neither will they yield a mile of acreage.

Kansas City (9-7) began 1981 in fast-forward, sprinting to 6-2. Then, the Chiefs rewound and unwound. Coach Marv Levy's question still has not been answered: at quarterback, Bill Kenney or Steve Fuller? If Joe Delaney (1,121 yards rushing as a rookie) can recover from surgery to repair a detached retina and if top selection Anthony Hancock (wide receiver from Tennessee) can use his world-class speed to outrun first-class coverage, the Chiefs might avoid a 1982 unwinding.

Seattle (6-10) remains the Jim Zorn (13 touchdowns, nine interceptions) and Steve Largent (75 catches) connection. Running back Theotis Brown (583 yards) returns, and top pick Jeff Bryant (defensive end, Clemson) should help a defense known for its secondary. And a team known for being of secondary importance.