While warming up for his 8:17 a.m. tee time, Howell felt a twinge in his side. It got a bit better before he injured it further after hitting a 3-iron, and he realized he wouldn't be able to play. He was scheduled to go off with Ted Purdy and Nick O'Nern.
'I've never had this happen before in 20 years of golf,' Howell said. 'No signs of it, physically, this week at all. But then I hit it in the rough nine times yesterday, so hacking out of the rough tightened things up a little bit, and this morning just put it over the edge.'
Casey didn't give a reason for quitting following the worst score of the first round. The 27-year-old, who made the headlines last November with anti-American remarks in an interview with the Sunday Times of London, played in his first Ryder Cup last year.
He was slated to start at 1:10 p.m. with Jerry Kelly and Jeff Maggert.
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