Rory McIlroy tumbled down the leaderboard at the Wells Fargo Championship after carding a second-round five-over-par 76.
McIlroy, who lay three shots off the lead after an opening 68, shot two birdies, five bogeys and a double-bogey six at the 11th to slip to two over for the tournament.
That was nine shots off the pace set by American Peter Malnati, who fired a 68, including two birdies in his final three holes, to go with his opening 67.
Aaron Wise and Jason Day were a shot back on six under par after a 68 and a 67 respectively, while England's Paul Casey was in a tie for fourth on five under with South Africa's Charl Schwartzel after a 68.
Tiger Woods joined McIlroy in struggling, following his first-round 71 with a 73 to sit alongside the four-time major winner on two under.