Substitute players are athletes who are not part of the starting lineup but can be brought into a game to replace a teammate. They are often used to provide fresh energy, adjust strategies, or respond to injuries. In many sports, such as soccer and basketball, teams have a designated number of substitutes they can use during a match. The role of substitute players can be crucial, as they can change the dynamics of a game. Coaches often decide when to make substitutions based on player performance, fatigue, or specific game situations. Effective use of substitutes can significantly impact a team's chances of winning.