MIAMI - Gary Sheffield agreed today to the largest contract package in baseball history, a $61 million, six-year extension with the Florida Marlins.

The contract runs from 1998 through 2003. In terms of total money it surpasses the $55 million, five-year contract Albert Belle signed with the Chicago White Sox. San Francisco's Barry Bonds is third at $43.75 million over six years.

Sheffield batted .314 last season with 42 home runs and 120 runs batted in.

The Marlins made the move after an offseason in which they committed more than $89 million to free agents, giving the money primarily to pitcher Alex Fernandez ($35 million over five years), outfielder Moises Alou ($25 million over five years) and infielder-outfielder Bobby Bonilla ($23.3 million over four years).

Sheffield, 28, is getting $6.1 million in 1997, the final season of a $24.45 million, four-year contract. His new deal calls for $10 million a season from 1998-2002 and $11 million in 2003. Florida has an $11 million option for 2004.

In addition, the Marlins will give Sheffield a $2.5 million salary advance on Jan. 6, 1998 - $500,000 for each of the first five seasons of the new contract.

Sheffield and the Marlins are believed to have agreed to most of the points of the deal in late February. But because extensions agreed to after opening day are not counted in calculations for a team's 1997 luxury tax, they held off announcing it until today.

Still, management's Player Relations Committee may investigate to see whether the deal should count to the Marlins' current payroll, a management official said on the condition he not be identified.

In addition to salary, Sheffield could earn a $150,000 bonus if he wins the National League's Most Valuable Player award, $100,000 if he finishes second, $75,000 for third, $50,000 for fourth and $25,000 for fifth.

He would get a $50,000 bonus each time he is elected to start in the All-Star game and $20,000 each time he's picked as an All-Star reserve. He also would get $100,000 if he's the World Series MVP, $50,000 if he's the league championship MVP and $25,000 if he's the division series MVP.

Additionally, he would get $50,000 each for winning Gold Glove and Silver Slugger Awards, and he receives a no-trade clause for the entire length of the deal.