American Billy Horschel has ended day two of the McGladrey Classic with a two-shot lead.
The 24-year-old finished on 12-under-par, while fellow American Webb Simpson was two shots further back after he carded a second-round 67.
Simpson is vying for the top spot in the PGA Tour's money list, and he needs to finish 15th to move ahead of England's Luke Donald.
Donald, who is not competing at this tournament, announced that he would be entering the tour's final event next week at Disney's Magnolia and Palm courses in Lake Buena Vista, Florida.
The world number one is currently $68,971 (£43,617) ahead of Simpson.