Despite the pleas of European captain Colin Montgomerie for potential Ryder Cup performers to play at the June 3-6 event, Karlsson has joined the list of withdrawals, which includes Padraig Harrington, Lee Westwood, Sergio Garcia, Paul Casey, Ian Poulter and Rory McIlroy.
Montgomerie now acknowledges that many European stars will not line up at the Wales Open.
"Ideally I'd like all 30 candidates to play but that is impossible," said Montgomerie.
"I managed that all, bar Sergio at the PGA Championship at Wentworth last week, and if the Wales Open was the week after the PGA I think more people would have stayed on, but because it is two weeks after, the players tend to disperse to wherever they are from in the world."
The 46-year-old Scot remained upbeat about the situation however, saying: "I'm quite happy that some of them have changed their schedule to accommodate the Wales Open and that is a very positive thing for the European Tour and the team."
One of those players to have changed his schedule is the world number 13, Luke Donald. He will be joined by another of the world's top 15, Martin Kaymer, whose only experience of the Ryder Cup thus far was as a special guest of 2008 captain Nick Faldo last time out.
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