If a Ryder Cup player is injured and cannot play in the Sunday singles matches, the "Envelope Rule" is invoked. This rule requires each team captain to submit a sealed envelope before the singles matches, containing the name of one player who would sit out if an opposing player is unable to compete due to injury or illness. If a player from one side is injured and cannot play, the player named in the opposing captain's envelope also sits out, and the match between these two players is considered a tie, awarding each team half a point. This rule was introduced in 1979 to handle such situations fairly, as all 12 players from each team are expected to play in the Sunday singles. It avoids forfeits and ensures both teams remain balanced in case of injury. The envelope is rarely opened, only if absolutely necessary. For example, if a player from Team Europe cannot play due to injury, the U.S. captain's envelope is opened, and the player named inside will sit out, with the match deemed a half-point draw. This rule has only been used a few times since its introduction and came into recent discussion with Viktor Hovland's neck injury in 2025 Ryder Cup, which might trigger the envelope rule if he cannot play on Sunday.
