SHEBOYGAN, Wis. (AP) -- Phil Mickelson isn't the only player capable of replacing Tiger Woods at No. 1.
For the second straight week, Woods is looking over his shoulder at two players who can end his record 270-week reign atop the world ranking -- Mickelson and Steve Stricker.
Stricker could go to No. 1 by winning the PGA Championship, provided Woods finishes out of the top 24 and Mickelson is out of the top three.
Mickelson would reach No. 1 for the first time with five scenarios: a victory in the PGA Championship; runner-up finish with Woods out of the top three; third-place finish with Woods out of the top 11; fourth-place finish with Woods outside the top 46; a two-way tie for fourth with Woods missing the cut.
Mickelson is being treated for a form of arthritis that surfaced just before the U.S. Open and left him in so much pain he couldn't walk.
He says he went to the Mayo Clinic in Rochester, Minn., after the British Open, and is on medication that brings the illness under control. There shouldn't be "any" issues long term, Mickelson said, and he is back to his normal practice schedule.
The arthritis is the latest health scare for Mickelson, whose wife and mother are battling breast cancer.
Woods is feeling much better about his game than he did a few days ago.
He arrived at this week's PGA Championship fresh off the worst tournament of his career. He beat only one player in the 80-man field at Firestone, shooting a whopping 18-over 298.
While Woods said Tuesday he's "frustrated" by his play at Firestone, he feels good about his work since coming to the PGA. His caddie has been holding the end of a club against Woods' head so he keeps it still through the swing.
Says Woods: "My head was moving way too much for me and my golf swing."
(Copyright 2010 by The Associated Press. All Rights Reserved.)