The five-time major golf champion Phil Mickelson remains in serious doubt for next week's Masters, having withdrawn from this week's Pro Am at the Houston Golf Open because of back problems.
Should the 43-year-old world number five miss the Masters, it'd mean the first of this year's Majors would lose a second major drawcard, with world number one Tiger Woods having also withdrawn from the event after back surgery.
Mickelson, though, remains in the draw for the first two rounds of the Houston Open which starts on Friday.
The Masters starts the following week at Augusta National in Georgia.
