How soon feathers can regain their sheen.

The fifth-place Baltimore Orioles, who used frugality and judgment to win the World Series in 1983, now appear to have bought their way back near the top.

The Orioles joined the big leagues of spending yesterday as they signed nine-time All-Star Fred Lynn to a five-year contract for $6.8 million.

Just five days ago, the Orioles looked like the offseason's free agent losers. Now, after signing Lee Lacy, the National League's No. 2 hitter, on Friday, then outspending the San Diego Padres for Lynn yesterday, Baltimore probably will prove to be the American League's biggest winter winner.

"This whets the appetite again," said General Manager Hank Peters after his second free-agent signing coup in 100 hours. "Jeez, spring training'll be here in just two months."

The Orioles, who shocked baseball a week ago by not signing Andre Thornton, whose asking price was $4.4 million for four years, dropped a comparable bombshell yesterday by offering center fielder Lynn more than a third of a million dollars a year more than current stars Eddie Murray and Cal Ripken Jr.

Lynn, who's averaged 22 homers, 80 runs batted in and a .280 average the past three seasons for the California Angels, should fill two of the Orioles' greatest needs: for a quality center fielder (Lynn has won four Gold Gloves) and for a No. 5 hitter behind Ripken and Murray.

"Baltimore made me the best offer," said Lynn, 32, from California, "and they are rich in winning tradition . . . I love playing in Baltimore and the fences seem to suit my (level of) power. There's no way I feel like an old man. I've been working out two months at my home, lifting weights and playing tennis."

Lynn's liabilities are his history of running into fences, returning slowly from injuries and occasionally becoming hors de combat against tough, left-handed pitching. Both in Boston and California he has raised eyebrows by missing crucial games. His nickname is "Fragile Freddie." Though Lynn plays with a hellbent style when intact, he also tends to be an art-for-art's-saker who plays for fun and hates to play hurt.

Lynn points out that he played in 142 games last season (hitting .271 with 23 homers and 79 RBI) and that in 17 of the 20 contests he missed, it was "the manager's decision" that kept him on the bench, not his injuries.

Voted AL rookie of the year and most valuable player in 1975, Lynn has been one of baseball's most graceful and popular players. His statistics in four years in California never approached those in Fenway Park (i.e., 39 homers, 122 RBI, .333 in '79), but Memorial Stadium, with its short foul lines, suits him better than the Big A.

"I would think it would be a tremendous burden on pitchers now because they can't pitch around Murray and Ripken like last year," said Lynn.

Lynn is, by far, the highest-paid player in team history. "It's not my ball club. It's Edward Bennett Williams'," said Peters. "He felt we should go ahead and do it. He wanted 'em and said, 'Go get 'em.' He had to bite the bullet.

"Our final offer to Lynn wasn't much different than the one that's been on the table for a while. Not signing Thornton didn't affect it," claimed Peters.

The Orioles still have a proposal out to Angels reliever Don Aase and remain extremely interested in trading for a regular second baseman. "We've managed to keep our pitching (second in the AL in ERA) intact," said Peters, who probably will offer an outfielder (perhaps Gary Roenicke) plus Rich Dauer and a prospect in trade for an infielder like Damaso Garcia of Toronto or Jack Perconte of Seattle.

The Orioles can be excused if they can't wait for spring training. The offense that scored 799 runs in 1983, one less than the major league high, may be back to peak form after a dismal '84 that produced 681 runs (ninth in the AL). The top of the order, with left fielder Mike Young and right fielder Lacy -- who had on-base percentages of .355 and .371 in '84 -- should be vastly better than the combinations last season that had an on-base percentage of barely .290.

Peters doubted that any of the Orioles would resent Lynn's salary, saying, "Everybody's making far more than they ever dreamed . . . The numbers have gotten so high that complaining about your salary has become sort of academic . . . We (the Orioles) have to become part of the (free-agent) system.

"The Yankees just got Rickey Henderson. Toronto traded for (star reliever) Bill Caudill. The Tigers got Walt Terrell. There are five damn good ball clubs in this division, but they all gave up something to get what they got. It's nice not to have to give up talent to get talent."

Williams was in Sweden yesterday, attending the Nobel Prize ceremonies. Given his team's payroll, perhaps the famous barrister was seeking advice from the new laureate in economics.