When the two captains submit their singles lineup on Sunday, they will also offer a sealed envelope containing the names of one player.
A player named by the envelope will sit from a single if the opponent has to withdraw due to illness or injury more than 30 minutes before the start of the first singles match.
Two players are considered a pair, so each side earns half the points.
If a player withdraws less than 30 minutes into which the first singles match begins, their match will be forfeited.
As soon as the team captain realizes the possibility of illness or injury of one of his players, they must immediately inform the opposite captain and chief referee.
The name of the envelope will only be revealed if it is in use.
An additional envelope was used in the 2021 Ryder Cup to blow straights in case the player had to pull out after testing positive for Covid-19.
Europe needs just 2½ points from 12 single matches to hold the Rider Cup. If Hovland withdraws from his match, they will only need the remaining 11 to 2 points.