Casey, Goosen and Villegas qualify as the highest-placed European, African and South American on the world rankings, while Allenby gets his chance because fellow Australian Geoff Ogilvy turned down his place.
Winner of the title at Wentworth three years, world number three Casey is back in action in Boston later this week after a rib muscle injury kept him out of the US PGA Championship and last week's opening leg of the US Tour's FedEx Cup play-offs.
"One thing I noticed when I won the World Match Play was the number of great players who made it their business to win the title at least twice," he said.
"Seve Ballesteros, Arnold Palmer, Jack Nicklaus, Greg Norman and Nick Faldo have all got their name on there at least a couple of times, so I will definitely be hoping to emulate them."
The event, with a first prize of nearly £650,000, takes place at Finca Cortesin near Marbella on October 29-November 1, with the 16-man field competing in four round robin groups and the winners of each going through the semi-finals.
Even those who finish bottom of their groups earn in excess of £100,000.
The complete field has yet to be determined and will be decided by the world rankings and European Tour "Race To Dubai" money list.
Tiger Woods is not expected to take up his spot as the leading North American player and both US PGA champion YE Yang and Ernie Els, who qualifies as the 2007 winner of the Match Play, could also be missing.