Irishman Padraig Harrington will launch his British Open title defense in the company of South African Retief Goosen and 1997 winner Justin Leonard of the US at Royal Birkdale on Thursday. Harrington, who triumphed last year at Carnoustie in a four-hole playoff with Spaniard Sergio Garcia, is scheduled to tee off at 0758 local (0658 GMT). Ernie Els, the 2002 champion at Muirfield, will play the first two rounds with Germany's Martin Kaymer and American Scott Verplank. South African Els is set to start his bid for a fourth major victory at 0831 on Thursday, three groups behind Harrington. Masters champion Trevor Immelman of South Africa has been grouped with American Anthony Kim and Denmark's Soren Hansen. The trio will tee off at 1353 in the opening round. In other high-profile groupings, world number two Phil Mickelson, Britain's Paul Casey and Hideto Tanihara of Japan will begin at 0920 on Thursday while third-ranked Australian Geoff Ogilvy will tee off at 0747 in the company of long-hitting American Davis Love III and Briton Oliver Wilson. Three-time champion and world number one Tiger Woods is a notable absentee this week, having been sidelined for the rest of this year while he recovers from reconstructive knee surgery. Australian Craig Parry is scheduled to hit the first shot of the 137th Open championship at 0630 on Thursday morning. Birkdale, on the north-west coast of England, is hosting the British Open for the ninth time.