Paul Casey will not take part in The Players Championship due to a back injury.
Casey's withdrawal was confirmed on Wednesday, the eve of the tournament, with Keith Mitchell taking his place.
The 40-year-old Englishman finished in a tie for fifth last week in the Wells Fargo Championship at Quail Hollow.
Casey had been due to tee off with Russell Knox and Alex Noren on Thursday, but world number 163 Mitchell has been handed a chance to impress.
