Now a broadside from the executive director of the Major League Players Association, Marvin Miller, accusing "some" player agents, and "one" in particular, of massively ripping off the baseball stars they represent.

Miller cited his union's fight for players' right to have agents negotiate their individual contracts, a right won in 1970, and said, in effect, at a New York press conference yesterday that they created a Frankenstein. Spelled Kapstein.

"We know of one agent," Miller stated - it didn't take much pressing to get him to add, yes, he meant Jerry Kapstein - "who got $115,000 out of the $150,000 bonus paid to the player by the club" signing a free agent. "This same man got $1 million over a two- or three-week period.

"In most cases a player isn't even present when negotiations are taking place . . . How do we know the agent is really getting the best possible deal for his client? How do we know that he hasn't made some bonus deal with the club to deliver that player?"

He cited Kapstein's "special covenant" offering the right of first refusal to a clun should a client get other offers after his contract expires; called the claim hy agents that they got only 5 or 6 per cent of the contract grossly inaccurate - "If he received the money up front in advance, he's really getting much more . . . Say a player signs a 10-year contract for $2 million and the agent receives $100,000 up front . . . His fee is more like 76.6 per cent of that player's first-year salary. It wouldn't be until after the 10th year that the agent has gotten only 5 per cent of the total package . . . If an agent is working on a percentage deal, a longer contract would be better for the agent regardless of the player's interest."

Some agents, said Miller, are gouging players on fees for mere clerical work.

Kapstein, reached in San Diego, retorted: "Marvin Miller is jealous . . . I only wish Marvin Miller put in the time I did. I've been at this for three or four years, seven days a week. Has any players stood up and said I cheated them or ripped them off?" . . .

The next great Notre Dame quarterback could be Rick Buehner from Louisville St. Xavier, 1975 high school player of the year in Kentucky - or Mark Herrmann, two-time first team all-Indiana for Carmel High. Buehner, 6-foot, 180-pound veer operative, signed his letter of intent Tuesday night. Herrmann, a lanky 6-5, 180 with 314 career pass completions for 4,327 yards, said he wanted to stay close to home and reckoned on Purdue - but Irish coach Dan Devine said "We still intend to go after him; we'll really give it a try" . . . The national binding letter day is Feb. 16 - but South Charleston, W.Va.'s record-busting ball-carrier Robert Alexander made it official he's all West Virginia U.'s, by signing yesterday before Gov. Jay Rockefeller and massed media in the governor's office . . .

Another deep freeze on the way, they say? But around the corner, we're reminded, spring along with the D.C.. Road Runners Club and look ahead to the fifth annual Cherry Blossom Classic distance run. A record field of more than 2,000 is expected for the 10-mile road race and accompanying two-mile fitness run. That's April 3, and same day, pro soccer at RFK: Diplomats' home opener, albeit an exhibition, vs. the Las Vegas Quicksilvers . . . Meantime, a four-game March 2 slate is farm for the first Eastern Eight basketball title tourney at Philadelphia's Spectrum: No 1 vs. No. 4 in the West, 1 p.m., No. 2 vs. 3. West, 3 p.m.; No.2 vs. No. 3, East, 7 p.m.; No. 1 vs. No. 4. East, 9 p.m. George Washington's in the East, and and league won't settle until March 4 semis intradivision or interdivision pairings to set up the March 5 final, winner to NCAAs . . . We recentlu had hotel basketball here, come Sunday for $10 entry fee you can play golf (putt-putt) in the first Tysons Ramada Inn-Door Open, noon to midnight - 15 holes in the Roosevelt Ballroom, three holes by the swim pool. Putters and caddies provided, plus a golf cart to carry players from the clubhouse (that's the lounge, but don't take "carry" too literally); some Redskins, some nice prizes . . .

Another college basketball player dropped dead on the floor, 6-5 junior Marshall Wiliams of Adephi U. on Long Island; the Brooklyn youngster collapsed 10 minutes into a game at Southampton College - "nobody around him at the time." Autopsy results pending . . .

Reginald Jordan, 18, killed ina car-train wreck at Chesapeake, Va., this week with a basketball teammate, Phil Bryant, 16, was being courted by college scouts who regarded him as one of the state's top prospects as a tight end in football . . . Dale Van Sickel, U. of Florida's first football all-America (1928), has died at 69 in Newport Beach, Calif. The stunt man-actor had been seriously ill since July, 1975, suffering brain damage when the car he was driving - supposed to go off the end of an oil-slicked wharf in a Walt Disney production - skidded into an abutment . . .

Newly retired L.A. Ram Merlin Olsen indeed has signed to be a network sports analyst - and actor - NBC announced yesterday . . . Arthur Ashe, unveiled on Wide World of Sports last week as a new ABC-TV personality - various sports, not only tennis - is a reported entrant in the $100,000 La Costa International Tennis Classic, March 21-27. Ashe must figure on his bad leg healing by the short end of the projected eight to 12 weeks he said he would be sidelined.