How Does the Ryder Cup Envelope Rule Work?

With the announcement of Viktor Hovland's injury after the Saturday Foursomes session, what happens if he cannot play in Sunday Singles?

There's an answer for that in the form of an envelope. Here's the official verbiage on what happens if a player can't compete in Singles:

When the Captains lodge their team selection for Singles play, they must provide a sealed envelope containing the name of one player who is regarded as having been paired with a player who, through illness, injury or other emergency reason, has to withdraw from the other side.

Such pairing is regarded as a tied match. If this requires the re-pairing of a match, this will be done down the order of the play. If two players (one from each side) withdraw, then they are treated as having been paired together (regardless of hidden selection) and the two other players from the particular matches will play each other.

FARMINGDALE, NEW YORK - SEPTEMBER 27: Viktor Hovland of Team Europe celebrates on the 17th green during the Saturday morning foursomes matches of the 2025 Ryder Cup at Black Course at Bethpage State Park Golf Course on September 27, 2025 in Farmingdale, New York. (Photo by Harry How/Getty Images)

This agreement covers withdrawal of only one player per side up to 30 minutes before the first Singles match commences for the day. The following clause covers a withdrawal, through illness or injury, from 30 minutes prior to the first match commencing until all matches have teed off.

If one player withdraws prior to the start of his match and subsequently, a player from the opposing team also withdraws prior to the start of his match, due to injury or illness, the two injured players are treated as having been paired together (tied match) and the other two non-injured players will be re-paired down the order of play as the final match.

If only one withdrawal is made in the period commencing 30 minutes before play, that player’s match will be forfeited.

As soon as a team captain is made aware of a possible illness or injury to one of his players, he should immediately notify the opposing captain and the Chief Referee of the injury or illness and of the possibility of either the envelope procedure or the 30-minute clause being implemented.

CLARIFICATION OF ENVELOPE SUBSTITUTE RULE FOR SINGLES
EUROPE USA
A vs H
B vs I
C* vs J
D vs K
E vs L*
F vs M

C & L are Captain’s hidden choices

Example 1: I has to withdraw

Then C is regarded as having been drawn against I and thus match C vs I is tied. B drops down to play J. Example 2 - A has to withdraw

Then L is regarded as having been drawn again A and they match A vs L is tied. H drops down to play E. Example 3 - M has to withdraw

Then C is regarded as having been drawn against M and thus match C vs M is tied. J drops down to play F.Example 4 - B & L have to withdraw

The B vs L match is tied and I drops down to play E.