BBC Sport's Ask Me Anything team explains what the Ryder Cup envelope is and why it might be used at Bethpage Black on Sunday.
A neck injury to Viktor Hovland means the rarely used envelope rule could come into play on the final day of the Ryder Cup at Bethpage Black in New York on Sunday.
The issue flared up following Hovland's Saturday morning foursomes victory with Robert MacIntyre against Scottie Scheffler and Russell Henley.
The Norwegian was supposed to play alongside Matt Fitzpatrick in the afternoon fourballs, but withdrew and was replaced by Tyrrell Hatton.
He went for an MRI scan on Saturday evening to determine the severity of the issue.
"I've had some issues with a neck injury on and off for the last two months," said Hovland.
"I'm going to get some treatment and hopefully I will be OK for the singles."
Hovland is scheduled to face Harris English in the final singles match at 19:03 BST, but if he is unable to play then the envelope rule will be used.
Europe hold an 11½-4½ lead going into Sunday's 12 singles - 14½ is the number required for victory.
What is the envelope rule?
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.
- McIlroy & Lowry silence New York crowd on famous European day
- Destined for greatness - why Donald's Europe are set to win Ryder Cup
Has the envelope rule been used before?
The envelope rule has been used just twice since it was introduced in 1979 following the Ryder Cup's expansion to include players from all of Europe.
In 1991, American Steve Pate sustained injuries in a car crash on the Wednesday before the event. He was able to play on the Saturday but was not deemed fit enough to compete in the Sunday singles.
The Europe envelope was opened and English rookie David Gilford was the man to miss out as the US went on to win 14½ - 13½.
Two years later Europe's Sam Torrance could not play on the Sunday because of an infected toe.
American Lanny Wadkins, who won 21½ points across eight Ryder Cups, was the surprise player to miss out. It later emerged he had volunteered to step aside so as not to deprive a more inexperienced player the chance to compete. The US won that Ryder Cup 15-13.
This article is the latest from BBC Sport's Ask Me Anything team.
What is Ask Me Anything?
Ask Me Anything is a service dedicated to answering your questions.
We want to reward your time by telling you things you do not know and reminding you of things you do.
The team will find out everything you need to know and be able to call upon a network of contacts including our experts and pundits.
We will be answering your questions from the heart of the BBC Sport newsroom, and going behind the scenes at some of the world's biggest sporting events.
Our coverage will span the BBC Sport website, app, social media and YouTube accounts, plus BBC TV and radio.
More questions answered...
- How does the Ryder Cup work?
- What are foursomes and fourballs?
- Who is the man on the Ryder Cup trophy?
Category: General Sports
