Like any political dogfight worth caring about, the struggle between former National Football League stars Gene Upshaw and Larry Csonka for control of the collective voice of the NFL players is laced with a healthy dose of old-fashioned mudslinging.

Csonka, the hard-nosed former Miami Dolphins fullback, launched a hard-nosed plan last month to form a new players' union, called the United Players of the NFL (UPNFL), to represent the players at the bargaining table. Csonka must collect signatures of 51 percent, or 751, of the 1,455 NFL players to become their legal bargaining agent. These plans have drawn heavy fire from Upshaw, executive director of the NFL Players Association (NFLPA), which Upshaw claims is no longer the players' bargaining agent, having decertified in November following a slew of legal action.

Upshaw sent out a four-page fax May 24 titled "Some Questions (and Answers) for Larry Csonka," which peppered the former all-pro with questions, answers and accusations on Csonka's football and after football life.

The NFLPA, which hasn't had a collective bargaining agreement with the owners since Aug. 31, 1987, hasn't been an official union since decertifying in November following an 8th U.S. Circuit Court of Appeals decision stating that the system of free agent compensation is beyond challenge at this time.

Upshaw has since taken the case to the U.S. Supreme Court, which last week said it had requested views from the Department of Justice on whether to hear the players' appeal.

The lack of a contract and a union has left the players' benefits -- such as pension funds and severance pay -- at the mercy of the owners, but the NFLPA is calling its strategy a success. Salary levels have risen dramatically since the last contract expired: A player's average salary in 1990 is expected to approach $400,000, up 43 percent from 1987, according to the NFLPA. The owners undoubtedly would push for a wage scale or a salary cap if negotiations were to reopen.

Csonka said unrestricted free agency, which Upshaw and his colleagues want for the players, "is not the utopia everyone thinks it is," and feels a settlement can be made without having to go through the courts. The difference between Upshaw and Csonka is the difference between litigation and negotiation. Csonka is willing to accept a restricted form of free agency in exchange for players' benefits; Upshaw is not.

"The average career of an NFL player is between 3 and 3 1/2 years," said Csonka, who was in Arizona trying to gather phone numbers and signatures. "They're asking these players to give up all their benefits. Most of the players will be long gone before any of these lawsuits get settled. And in the meantime, if you're one of those players, you're left out in the cold. You have lost the funding for your pension program. Your severance accrual has stopped.

"They say the average salary has risen dramatically. Well, if I'm one of the top quarterbacks in this league, I have nothing to worry about. I have everything I want. But if I'm a lineman, not a big-name star, I'm being cheated out of everything that should be coming my way. Where do I go?"

Csonka said his free agency plan, which he feels the owners would accept, borrows from Major League Baseball's setup, which stipulates that a player can become a free agent after six years of service.

The NFLPA, however, insists Csonka is a tool of management, claiming that the NFL Management Council (the owners' negotiating group) is backing him. "He is being paid and financed by the NFL Management Council," said Upshaw. "It's that simple. Look, you tell me how a guy walking around on a farm in Ohio {where Csonka lives} suddenly says, 'I know the answers.' We're talking about complex issues you just can't find out about on a farm."

Csonka and the Management Council both deny the NFLPA's charge.

One specific issue contained in the fax implied that the NFL Management Council gave Csonka the phone numbers and addresses of all 1,455 NFL players.

"There's only two places he could've gotten that information, and that's from us or from the Management Council," said Upshaw. "And we certainly were not going to give them to him."

Csonka, however, insists that isn't true. In fact, he said he has been "scouring the countryside," gathering phone numbers from anyone who will help him, but has found only about 900 so far.

"I'm no puppet," he said, responding to Upshaw's characterization. "That upsets me. The owners don't like me one bit. I don't need this job. I made over 300,000 dollars last year from my endorsements and speaking engagements. I want this job."