Mickelson, a 46-year-old US left-hander, underwent surgery on October 19 and again December 12 but has been hitting balls since January 12 and played a practice round before teeing off Thursday at LaQuinta Country Club in the California desert.
"I feel good and I want to play," Mickelson said. "I don't know where my game is, but I figure the only way to find out is to play."
Mickelson, who shared third at the event last year, ends a three-and-a-half-month layoff since he shared eighth in the Safeway Open last October. He has slid to 21st in the world rankings.
The three-time Masters champion, seeking his 43rd career PGA title and first victory since the 2013 British Open, tees off at 8:40 am alongside compatriot Bill Haas, a two-time winner of the event.
