Woods' No 1 spot in danger as Mickelson returns to Colonial

'Lefty' to make emotional comeback to tournament he won in 2008

FORT WORTH, Texas - Tiger Woods' world No 1 ranking is on the line again this week but Phil Mickelson said his only chance of seizing the top spot is to put the matter out of his mind.

"It would be something very special," Mickelson said of the chance to gain the No 1 ranking for the first time in his career.