Brooks Koepka lamented his putting after struggling to a one-over 71 at the WGC-FedEx St. Jude Invitational on Friday.
The overnight leader dropped to a tie for third, four shots adrift of Brendon Todd (65) at the halfway mark of the PGA Tour event in Memphis.
Koepka rued his performance with the putter in the second round, in which he mixed three birdies with two bogeys and a double bogey.
"I just putted bad. It wasn't really anything other than that. Felt stress-free other than just missing some short ones," the American defending champion said.
"On the back nine they felt good, they were just missing, and on the front they just weren't good putts."
Koepka added: "I felt like I did everything we were trying to do, just wasn't working, wasn't seeing the line.
"Even yesterday I said I didn't feel quite comfortable over anything inside five feet and today it just felt kind of the same."
Koepka is tied for third with Chez Reavie and Byeong Hun An, two shots behind Rickie Fowler and four adrift of Todd.