That saw changes at the top of the leaderboard, with second-round leaders Min Woo Lee and Akshay Bhatia carding rounds of six-over and three-over respectively.
American J.J. Spaun took over at the top after his two-under 70 saw him improve to 12-under for the tournament with a one-shot lead on compatriot Bud Cauley.
Northern Irishman Rory McIlroy, who shot a one-over 73 on Sunday, said the conditions made it tricky, but also meant it would be possible to make up a deficit of more than four shots in Monday’s final round.
“I think with these conditions it is,” McIlroy said.
“I feel like every bogey was really soft. I could have shot something in the 60s. I have to at least be encouraged by how I hit it and how I controlled myself around there. I just need to chip and putt better tomorrow.
“I think when you’re a little further back, you’d rather have some testing conditions.”
Fox will be among the first players to get under way on Monday morning, playing in the first group to go from the back nine alongside Americans Jordan Spieth and Joe Highsmith.
Christopher Reive joined the Herald sports team in 2017, bringing the same versatility to his coverage as he does to his sports viewing habits.