The 21-year-old Australian withdrew because his father was in a boating accident. It is not yet know how serious the accident was.
Scott won last year's event with a 21-under-par total of 267, edging out then fellow 20-year-old Justin Rose.
Rose, 14 days younger than his counterpart, matched Scott's closing round of 69. But the Johannesburg-born Englishman, who reached international prominence by finishing tied fourth in the 1998 Open Championship as an amateur, could not quite force a play-off.
Three major champions are in a top class field at Houghton. Retief Goosen, the reigning U.S. Open champion and 2001 Volvo Order of Merit winner, attempts to win the title for the first time while Ernie Els, who collected the U.S. Open trophy in 1994 and 1997, aims to secure a second title following his 1999 success.
Also competing is 1999 British Open Champion, Paul Lawrie, and both he and Els have reason to recall their last close encounter in a event under the same sponsorship banner, the Dunhill Links Championship at St. Andrews last October.
On that occasion Els looked on as the Scot holed a 40-foot birdie putt from the 'Valley of Sin' on the Old Course to secure the title, an $800,000 first-prize and the prestigious European Tour Shot the Year Award.
Other past champions taking part are Germany's Sven Struver, successful over 54 holes in 1996, and Anthony Wall of England, who triumphed in the first European Tour event of the new millennium in January 2000 and finished a creditable fifth last year over a course he clearly enjoys.
Wall commented: 'It's a very good test. It's always in great condition too, even when it had the amount of rain we experienced when I won in 2000. It holds up excellently and shows how well the course is designed.'
Andrew Oldcorn, the Volvo PGA champion, returns to action following a lengthy spell on the sidelines due to injury while the new season starts for another Scottish winner on the 2001 European Tour schedule, Andrew Coltart.
Also hoping to make an impression are the last three winners of the European Tour Qualifying School - Alastair Forsyth of Scotland, South African Desvonde Botes and the most recent recipient of the No. 1 card, Sweden's Johan Skold.
Houghton is one of the well-established Johannesburg courses which has hosted many tournaments over the years, including the South African Open. It is regarded as a demanding layout with a selection of interesting holes on an attractive track of land containing old trees and flowering shrubs.