Paul Casey has withdrawn from The Players Championship after picking up a back injury ahead of the PGA Tour's flagship event of the season.
Casey, 40, underwent treatment on the problem upon his arrival at TPC Sawgrass on Wednesday but was advised by medical staff to bypass the tournament in order to prevent further damage.
The Englishman has enjoyed a golden run of form recently, highlighted by ending a nine-year winless spell on Tour at the Valspar Championship in March and a total of 21 top-20 finishes from his last 26 worldwide starts.
The world number 12 also withdrew from The Players in 2015 due to illness and in 2012 when sustaining a shoulder injury on day one.
Casey's best result in the tournament was a tie for 10th on his debut in 2004.
Keith Mitchell replaces Casey in the field and he joins a threeball consisting of Russell Knox and Alex Noren.