First baseman Eddie Murray signed a five-year contract extension today that will keep him tied to the Baltimore Orioles through the 1991 season, and, it is believed, will make him the game's highest-paid player.

No dollar terms were revealed, but the salary was believed to be about $13 million and General Manager Hank Peters said, "This is the largest contract ever given to one of our players.

"We're very happy that Eddie wants to spend his career with the Orioles. He's been remarkably consistent through the years and this contract is one that rewards his past accomplishments, as well as those we are confident he will achieve in the future."

Boston's Jim Rice and Philadelphia's Mike Schmidt reportedly make about $2.1 million a year.

In 1980, Murray signed a five-year contract, plus an option year, that made him an Oriole through 1986. A month ago, he was close to signing the extension that was completed today, but it took this long to work out the language.

Ron Shapiro, Murray's agent, said, "We're pleased that this lengthy negotiation has been completed in the style of Eddie Murray and the Orioles -- quiet and effective discussions, leading to a conclusion that satisfies all parties and distinguishes Eddie as the best."

Murray (.298 lifetime) has had at least 170 hits, 25 homers and 88 runs batted in during each of seven full campaigns. Even in the strike-shortened 1981 season, he led the American League with 78 RBI and shared the homer lead with 22.

Although slumping lately -- with one hit in his last 21 at bats -- Murray ranks second in the league in RBI with 105 and third in runs scored with 91. He has 24 home runs.