Els leads last year's winner Padraig Harrington by $313,892 in the European Tour standings, but could be surpassed this weekend as he is playing in Singapore -- not Sotogrande -- on the Asian Tour.
England's Justin Rose and Swedish players Niclas Fasth and Henrik Stenson can also pass Els for the season-ending money title with a victory at Valderrama, Europe's richest tournament at $5.8 million with first-place worth $960,488.
Els, who won the title in 2003 and 2004, is under a three-year contract to play in Singapore and criticized the European Tour for the scheduling conflict.
'I'd love to play the Volvo Masters, but if they screw up the dates, so be it,' Els said Wednesday. 'You can't please everybody and especially when two big events like these are being played on the same week. Somebody missed the ball, it's as simple as that.'
The European Tour wouldn't comment on Els' remarks.
Eight-time Order of Merit champion Colin Montgomerie didn't accept Els' excuse, and was disappointed that only 51 of the 60 qualifiers were at Valderrama.
'Deals could be done where they could have played two out of the next three years or something like that, or whatever the case may be, but this should be a priority,' Montgomerie said. 'The Order of Merit means a lot to me and it obviously doesn't mean a lot to others.'
Harrington said he had signed a contract to play at Singapore, but had a get-out clause in case he was able to defend the Order of Merit.
'Right from the go as European No. 1, my place to be was here,' Harrington said. 'As golfers, we're spoiled for choice. I think the tour did everything in their powers to accommodate the clash.'
U.S. Open champion Angel Cabrera and the 2001 and 2004 U.S. Open winner Retief Goosen were two of the big names missing from Thursday's draw.
Harrington arrives as a top contender to take the Harry Vardon trophy, just as he did in 2006, but will face stiff competition from Rose.
Rose has played in only 11 European tournaments to Harrington's 14 but trails the Irishman by only $949.
'Obviously it's a very exciting situation and one that I would love to capitalize on,' Rose said. 'I've played a very limited schedule, it's the kind of opportunity that I think for me would be a huge achievement. It would be a career highlight.'
However, Rose is struggling to overcome a back injury he re-aggravated at the Portugal Masters two weeks ago.
With Els missing, Harrington and Rose will tee off together in Thursday's final pairing with both players hoping the race goes down to the wire.
'I'm hoping that Justin plays well tomorrow, because if my partner plays well I usually play well,' Harrington said.
Defending champion Jeev Milkha Singh of India is one of nine former winners in the field to commemorate the 20th anniversary of the competition, which is only open for the European Tour's top 60 players.