Spaniard Jiménez and Irishman McDowell are both winners on The European Tour already this year McDowell claiming both the Ballantines Championship and The Barclays Scottish Open – while the consistent Karlsson, of Sweden, has six top five finishes including two as runner up.
The trio, who are all in the top five on the Order of Merit, will be joined in the field at Golf Club Gut Lärchenhof in Cologne, Germany, by South African Retief Goosen, winner of two Order of Merit crowns in 2001 and 2002.
Goosen, who finished tied fourth behind winner Vijay Singh at the World Golf Championship Bridgestone Invitational, will be looking for his second title at Gut Lärchenhof, following his victory in 2005.
Crowd favourites John Daly and Colin Montgomerie will also compete for a share of the 2,000,000 prize fund in the final European Tour event before The Ryder Cup.
Scotlands Montgomerie won the title in 1998 en route to his sixth out of a record eight Order of Merit crowns and will be chasing his first European Tour victory of 2008.
He will join Australian Stuart Appleby, Masters Tournament winner Fred Couples, Daniel Chopra of Sweden and defending champion Søren Hansen of Denmark in the strong field.
Bernhard Langer will front the home contingent along with Martin Kaymer, who claimed an emotional victory the last time The European Tour visited Germany for the BMW International Open in June.