US Tour:Phil Mickelson's scheduled debut on the 2008 PGA Tour at this week's Buick Invitational was in doubt when the world number two was confined to bed with a respiratory problem.
Mickelson, a three-times winner at Torrey Pines Golf Club, has been struggling with shortness of breath and fatigue since October, his manager TR Reinman said in a statement.
"His immediate goal is to be well enough to play in the Wednesday pro-am so that he can compete in his first event of the season," Reinman added.
"It's unclear whether the condition was caused by working in the smoky debris on his property following the (October and November) wildfires that devastated Mickelson's neighbourhood or by the illness he developed immediately after that in Singapore.
"He managed to win the HSBC Champions the following week in Shanghai but has not felt 100 percent since then. Mickelson's condition worsened over the weekend and the doctor gave his order this morning."
Mickelson has not played tournament golf since winning the HSBC Champions in a three-way play-off two months ago. The 37-year-old American had been hoping to make his 2008 Tour debut this week before playing in the next four events on the West Coast swing.
