American Luke Guthrie has earned a one-shot lead after day two of the Honda Classic in Florida.
Guthrie followed up Thursday's round of 68 with a 63 at Palm Beach Gardens to leave him on nine-under-par overall.
However, the story of the day was world number one Rory McIlroy's withdrawal from the tournament midway through his round.
The defending champion claimed that he was suffering with wisdom tooth pain after he dropped seven shots in his opening eight holes.
Michael Thompson will start Saturday one shot behind his fellow countryman Guthrie, while Canadian Graham DeLaet joins Boo Weekley on seven-under.
A 68 has left England's Lee Westwood on six-under with six others, including compatriot Justin Rose.
Graeme McDowell is among a host of players on five-under and Keegan Bradley carded a 68 to give him a score of four-under.
Meanwhile, overnight leader Camilo Villegas suffered miserably on day two as a round of 77 saw the Colombian miss the cut.
