The St. Louis Cardinals have obtained right-handed pitcher Jose DeLeon from the Chicago White Sox in exchange for left-hander Rick Horton and rookie outfielder Lance Johnson.

DeLeon, 27, won six of his last seven decisions in 1987 to finish 11-12 with a 4.02 earned run average. He has a career record of 32-55, including a 2-19 mark with the Pittsburgh Pirates in 1985.

Horton, 28, is 24-12 with 14 saves in four seasons with the Cardinals; 8-3 with seven saves last season. Johnson hit .333 for Class AAA Louisville last year and was the American Association MVP and rookie of the year. To make room as starting center fielder for Johnson, the White Sox have moved Kenny Williams to third base . . .

Don Baylor, with 331 big league home runs and looking to play on his third straight American League pennant winner, signed with the Oakland Athletics and said the team's main selling point was the promise of at least 300 at-bats in the coming season.

At least three other clubs were interested in Baylor, 38, and one, the Kansas City Royals, made an offer that included a front office job after his playing days.

"I'm still a player and want to be a player," he said. "That {the future} wasn't in my thinking."

His salary with the A's, with whom he also spent 1976, will be less than half his $950,000 salary with Boston and Minnesota . . .

The Cleveland Indians continued active in the free-agent market, signing left-handed pitcher Dan Schatzeder and right-handed power hitter Ron Kittle. Last month the Indians picked up ex-Texas right-hander Greg Harris and ex-Seattle outfielder John Moses.

Schatzeder, who spent 1987 with the Phillies and Twins, gets $325,000; Kittle, late of the New York Yankees, $300,000. Both have incentive bonus clauses . . .

A news conference is scheduled Thursday to give details of an exhibition between the New York Mets and Baltimore Orioles April 3 at RFK Stadium.