Mickelson, who opened the tournament Thursday with a three-under-par 69 on the North Course, struggled to keep pace with the contenders Friday as he shot a one-over 73 in the second round on the tougher South Course.
Although he reported having some pain in his back following the round, he was hoping to at least attempt to play in the third round on Saturday.
A few hours after his round, though, the
Mickelson, who does not have a history of back problems, reached the midway point of the tournament eight shots behind leader Jordan Spieth.
"I love this tournament and I want to play here," Mickelson said after his round, when he still had hopes of continuing to play this weekend. "I love playing in San Diego, and this is a place where I grew up playing, so I really want to play."
But Mickelson, who said he felt the
"I have the entire year," Mickelson said. "I've got majors coming up. I've got other tournaments coming up and I don't want to get in bad habits. My game is pretty sharp getting ready to start the year and I could tell I'm making terrible swings out there relative to the way I've been swinging."
Mickelson is scheduled to play next week in the