In baseball, the head coach of a team is called the manager
The manager controls all matters of team strategy on the field and team leadership. The manager sets the line-up and starting pitcher before each game as well as making substitutions, and edits throughout the game.
How much control a manager takes in player strategy varies from one manager to another. Some managers control pitch selection, defensive positioning, decisions to bunt, steal, pitch out, etc., while others leave these decisions to a player's discretion or another coach. Most managers find a balance somewhere in the middle. The General Manager of a team typically controls player transactions and bears the primary responsibility on behalf of the ballclub during contract discussions with players.