Phil Mickelson will miss the HSBC World Match Play Championship at Wentworth to attend his sister's wedding.
Mickelson would have been guaranteed a place at Wentworth
The world number two has opted to forgo the event, starting on 14 September, but will leave the celebrations early in order to join the US Ryder Cup team.
His absence is offset by the confirmed attendance of Tiger Woods, who is treating the event as a warm-up for the Ryder Cup against Europe.
Woods is appearing in the World Match Play for the first time since 1998.
Just how many other members of the US or European Ryder Cup sides end up in the 16-man field at Wentworth remains to be seen.
Qualified so far are Woods as world number one, New Zealand's Michael Campbell as defending champion and England's David Howell and Simon Khan from their displays in designated European Tour events.
Two more places will be filled from the European Order of Merit, with Robert Karlsson and Paul Casey in pole position.
And a further 10 will be selected from a table based on performances in the majors this year.
Mickelson leads that, but with him set to decline the invitation, the next are: Geoff Ogilvy, Jim Furyk, Tim Clark, Chris DiMarco, Ernie Els, Colin Montgomerie, Angel Cabrera, Retief Goosen and Jose Maria Olazabal.
This week's USPGA - the last major of the season - will finalise the pecking order for places.