Jack McKeon resigns as manager of the Padres but keeps his position as San Diego’s vice president of baseball operations. He is replaced in the dugout by Greg Riddoch. Later in the season, McKeon will lose his front-office job as well.

On July 11, 1990Jack McKeon resigns as manager of the Padres but keeps his position as San Diego’s vice president of baseball operations. He is replaced in the dugout by Greg Riddoch. Later in the season, McKeon will lose his front-office job as well.

Source
Baseball Reference July 11