Ken Boyer, manager of the Rochester Red Wings of the International League and a former major league player, was named manager yesterday of the St. Louis Cardinals of the National League.

August A. Busch Jr., chairman of the board and president of the team, said in a brief statement that Boyer was chosen "after consideration of a number of candidates."

Boyer takes over from Vern Rapp, who was fired as manager of the Cardinals Tuesday while the team was in Montreal.

Boyer, 46, retired from active playing in 1969 after 15 years in the majors, 11 of them with the Cardinals. He played most of his career at third base. He managed five seasons in the Cardinal organization, including three years at Tulsa, the Cardinals' top farm team.

He was bypassed by the Cardinals in October of 1976 when the team chose Rapp to manage the team.

To show his disappointment with Rapp's selection, Boyer left the Cardinal organization and was in his second season with the Red Wings, a Baltimore Oriole farm club.

Cardinal Vice President Bing Devine contaced Hank Peters, general manager of the Orioles, Thursday about Boyer's availability. Peters said Devine asked him about Boyer's performance at the Orioles' Rochester farm team and that he gave Devine a favorable report as well as permission for Devine to contact Boyer.

"I would not stand in Boyer's way," he said.