Leon Spinks, who a year ago today was on the eve of taking the heavyweight championship from Muhammad Ali, was the derby-hatted (with red feather, yet) man of the hour yesterday as plans began to jell toward crowning a successor, again, to Ali.

Spinks accepted the apologies of Top Rank promoter Bob Arum at a press conference in New York's Waldorf Astoria Hotel -- apologies for having cast aspersions on the way Spinks prepared for his losing title defense against Ali in New Orleans Sept. 15. Arum introduced Spinks, who has not fought since, as the key fighter in the proposed fourman elimination tournament to install a World Boxing Association champion now that Ali is (presumably) retiring.

Arum, expecting Ali to confirm "in the next few weeks" that he has fought his last, announced a proposed May bout matching Spinks and Kallie Knoetze, the South African embroiled in litigation for the right to box in the United States. Site: Nevada or Monaco.

The winner would fight the survivor of the elimination bout between Gerrie Coetzee, the other South African contender, and the winner of Saturday's Duane Bobick-John Tate match in Indianapolis.

That takes care of WBA. Meantime, Larry Holmes reigns as World Boxing Council champ. And Ken Norton says it's Holmes whose crown he is after -- Norton won't fight any South African. Norton opposes Earnie Shavers on March 23 in Las Vegas and ABC-TV will show that bout on the same primetime bill with Holmes' title defense against Ossie Ocasio, who put Jimmy Young out of the picture.

At any rate, Spinks says he's got his head on straight now, derby and all.

Bubba Smith, the massive old Baltimore Colt, has lost his $2.5 million damage suit against the National Football League -- retired in Tampa after last year's trial ended in a hung jury. A six-member federal court jury this time ruled there was no negligence on the part of the NFL or two accused officials when Smith suffered a knee injury that sent his illustrious career plummeting. It happened in a Baltimore-Pittsburgh exhibition game in 1972; Smith later contended the sideline officials were at fault for failing to get the downs marker out of the way before he slammed into it, wrecking the knee.

Chuck Foreman is knocking Minnesota again, and as to the NFL trade rumor of Miami defensive end A. J. Duhe and a No. 1 draft choice to the Vikings for running back Foreman, he avers: "I'd look at any change like that as something that would help me... If it happens, fine. The Dolphins have a great coach, a great line -- all the things I need to do my job."

It's a deal, WTOP radio and the Baltimore Orioles, for 1979 and 1980 (if necessary): a minimum of 140-150 games each season, depending on conflicts with Dips soccer. At last, baseball fans, some weighty Washington wattage -- and, as Metro Communication Sports' Len Klompus put it, "a firm commitment by WTOP to baseball, hopefully until we get a team here." All r-i-i-ght.