Greg Norman has turned down the chance to play in next week&aposs US PGA Championship in Detroit. An invitation was issued to the 53-year-old Australian after his spectacular attempt to become the oldest winner in major history in The Open at Royal Birkdale. Outright leader with 18 and nine holes to play, Norman finished joint third. He subsequently shared fifth position in the Senior British Open at Royal Troon on the weekend. Norman&aposs next goal will be the US Seniors Open starting at Broad Moor in Colorado Springs on Thursday. After playing just a handful of events this year prior to Birkdale, a fourth event in as many weeks was one too many for Norman. “It&aposs a great honour to be thought of in that regard,” said the former world No.1 last week after receiving the invitation. Darren Clarke, who missed the 2006 US PGA the week after his wife Heather died of breast cancer but returned last year to finish 42nd, has accepted an invite. The field is, of course, without Tiger Woods, winner of the title the past two years, but it does include American Ryder Cup captain Paul Azinger, champion in 1993 after a play-off with Norman. Previous captains have had wildcard decisions to make at the end of the final major of the year, but Azinger is taking three extra weeks to decide his four picks. Two spots in the PGA field are kept open in case the winners of this week&aposs Bridgestone world championship in Akron and Reno-Tahoe Open are not exempt. German Alex Cejka is amongst the reserves waiting to discover if that is the case.