John Jefferson, Green Bay Packer, materializes today, last week's trade from San Diego concluded at last. The all-pro pass receiver agreed to terms yesterday under which the Packers will discard Jefferson's Charger contracts through 1986 in favor of beefier stuff through 1984.

By no means do the Chargers come up empty. They wrung a No. 1 and two No. 2 draft choices between 1982 and '84 out of the Pack -- and have until Feb. 1, 1982, to determine they year in which they want Green Bay's No. 1; plus S.D. gets the right to switch first-round picks with the Packers in either of the two years they get No. 2s; plus S.D. gets Aundra Thompson, pre-Jefferson partner of James Lofton on the Green Bay flanks.

Jefferson is due in Wisconsin today to sign and to undergo a physical he hopes will prove he is in great shape despite the 1981 idleness he chose in preference to performing further under the nine years of contracts he signed, in rookie ignorance, as a 1978 first-round draft pick. Green Bay brass says his pay will not be out of line with club scale, probably meaning he'll make $250,000-a-year-apiece bookends with Lofton . . .

Mark May, the Redskins' 1981 No. 1 draftee, recently donated $10,000 to alma mater Pitt's alumni sports fund. "It just seemed like a good gesture," the big fellow told the weekly Panther football luncheon by telephone. Besides, he allowed, that was as nothing to the deal he just closed for a house in Northern Virginia: "It was the fastest I've ever seen money go through my hands." He laughed, sort of . . .

Here's Landslide, favored in today's pacing classic, the Little Brown Jug at Delaware, Ohio, already syndicated for stud in a $3.6 million deal on the eve of the race. The colt, a $290,000 auction buy as a 1979 yearling, went unraced as a 2-year-old and didn't debut at 3 until July 28, but since then, zoom: 9-0, with a worst mile of 1:57 4/5, a best of 1:54 4/5, and evidently he'll never set foot to track at 4. One of Landslide's major owners, and he'll retain a breeding interest, is William E. Simon, the former Treasury secretary, current U.S. Olympic official and Republican stalwart -- explaining, perhaps, why the horse no longer has its original name of Tammany Hall . . .

Vitas Gerulaitis, last heard telling the umpire and all us TV eavesdroppers after John McEnroe's match-point shot that "the (blankety-blank) ball was a foot over the (censored) line," has begun serving a 21-day suspension from the Volvo Grand Prix circuit, automatic for a 12-month accumulation of minor offenses . . .

Oh-oh, vote of confidence for Coach Walt Michaels from the N.Y. Jets' president, Jim Kensil, after Opponents 100, NYJ 40 in an 0-3 start: "Management is fully satisfied he's coaching to the best of his ability . . . the way he's worked with the team and how he prepares them". . . .

A. In 1961, Carl Bouldin contributed 16 points to the Cincinnati Bearcats' 70-65 overtime upset of Ohio State in the NCAA basketball final, and, still in 1961, pitched in two games (0-1) for the Washington Senators . . . Q. Whatever happened to Jackie Jensen?