Tiger Woods drops to eighth in rankings
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Casey moved up to seventh in the rankings released Monday despite missing the cut last week at the Wells Fargo Championship.
Woods skipped the event because of knee and Achilles' tendon injuries.
Fourth-ranked Phil Mickelson of the United States is now the only non-European player in the top seven.
Woods is returning to competition at The Players Championship on Thursday.
His coach, Sean Foley, says he has been walking in a protective boot.
Information from The Associated Press was used in this report.