What is required for a player's substitution to occur without penalty?

For a substitution to occur without penalty, it is essential that the player is listed on the lineup card. This requirement ensures that the team's roster is accurately represented and that the opposing team is aware of the eligible players. It helps maintain the integrity of the game by preventing unexpected or unauthorized changes to the team's roster during play.

Having a player approved by the umpire or entering only during a timeout are procedural aspects, but they do not solely guarantee that a substitution is valid. The status of the player needing to be on the lineup card specifically addresses their eligibility to play in that game. Additionally, requiring that a player must have participated in a previous game does not relate to the validity of a substitution; a player who meets the lineup requirements can be substituted in regardless of past game participation. Thus, being listed on the lineup card is the critical factor for a valid substitution.