World number 31 Thomas Bjorn has pulled out of this week's WGC-Accenture Match Play Championship in Carlsbad, California because of a sore neck.
The 35-year-old Dane woke up with the injury at the weekend and is due to have treatment over the next few days, a spokeswoman for his London agents, IMG, said on Monday.
Bjorn, a runner-up in two British Opens and one U.S. PGA Championship, had been scheduled to play John Daly in Wednesday's first round.
His withdrawal means Briton Graeme McDowell will now take on world number two Vijay Singh in the opening round instead of the top-ranked Tiger Woods.
Bjorn is the second leading European to pull out of the opening World Golf Championships event of the year. World number six Sergio Garcia of Spain decided not to compete.
Woods has won the title in two of the last three years.
A revised draw for the first round will be announced later on Monday.