Ryder Cup: What is the envelope rule and how does it work?

When the two captains submit their singles line-up for Sunday, they also provide a sealed envelope containing the name of one player.

The player named in the envelope would sit out the singles if an opponent had to withdraw through illness or injury more than 30 minutes before the start of the first singles match.

The two players would be regarded as a pair so each side would take half a point.

If a player withdraws less than 30 minutes before the first singles match starts, their match is forfeited.

As soon as a team captain is made aware of possible illness or injury to one of his players, they must immediately inform the opposing captain and chief referee.

The names in the envelopes are only revealed if they are used.

An additional envelope was used at the 2021 Ryder Cup at Whistling Straights in case a player had to pull out after testing positive for Covid-19.

Europe need just 2½ points from the 12 singles matches to retain the Ryder Cup. If Hovland withdraws from his match then they would need only two points from the remaining 11.