The two-year, guaranteed contract John Riggins signed in March will pay him $1.6 million but, because of a uniquely structured annuities system, will cost the team $1 million, it was learned.

In all, including deferred money from Riggins' initial Redskin contract (signed in 1976), Washington will owe the veteran fullback about $2.6 million upon his retirement.

The Redskins have refused to disclose terms of the contract, which makes Riggins the highest-paid Washington player ever and one of the highest-paid athletes in the National Football League this fall.

Riggins' new contract calls for him to receive $500,000 in both 1983 and 1984. He will be paid $100,000 each year in salary, with $400,000 deferred each season.

According to terms of the contract, the Redskins already have purchased a $400,000 single-premium annuity for Riggins with the 1983 deferred money. An annuity is normally purchased from an insurance company, which then guarantees that it will pay fixed sums at regular, future intervals; in this case, those payments would be made to Riggins. The amount of the payments is determined by the interest rate paid on the original investment.

Riggins' annuity comes due on Sept. 1, 1985, which is when he will begin receiving monthly payments of $6,586; they will continue monthly for 10 years. By the final payment, Riggins will have received $790,320 from the annuity.

In addition, the Redskins are required to purchase another $400,000 single-premium annuity with the 1984 deferred money.

That second annuity comes due on the same date, at which point Riggins will begin receiving monthly payments of $5,112 over a 10-year period. By the final payment, Riggins will have received $613,440 from the second annuity.

The agreement is contrary to the policy established by owner Jack Kent Cooke, who has said he does not guarantee player contracts. This contract contains both performance and injury guarantees, which means Riggins will be paid even if he doesn't play over the next two seasons. The agreement also contains a clause that says Riggins can't be traded without his consent.

Although Riggins has not announced his plans, it is apparent from terms of this new contract that he is anticipating retiring after the 1984 season, when he will be 35.

Besides the annuity payments, the team still owes him almost $1.2 million in deferred payments from his first contract. That contract paid Riggins $100,000 a year, with $200,000 withheld annually, except in 1982, when a players union strike shortened the schedule. Starting 30 days after he notifies the team of his retirement, he will receive annual $100,000 installments until that deferred money runs out.

The Redskins signed Riggins to a new contract after he received a three-year, $2.5 million offer from Michigan of the U.S. Football League. Riggins, the most valuable player in Super Bowl XVII and the seventh-leading rusher in NFL history, negotiated the Washington contract with Cooke at the owner's Upperville, Va., estate.