World number one Scottie Scheffler is three further back. The American, who has already won six times this year, including the Masters in April, hit a 70 to join compatriot Billy Horschel (68) and South African Dean Burmester (69) on two under.
Australia’s Jason Day had a bogey-free 68 and sits alongside Canada’s Corey Conners (70) on one under.
Patrick Cantlay and Xander Schauffele are also on that mark although Cantlay’s 68 was four shots better than his good friend could manage to leave only 10 players under par.
The halfway cut mark, which sees the top 70 players and ties play the final two rounds, came at six over par.
Scotland’s Robert MacIntyre is in on five over, while Northern Ireland’s Rory McIlroy is heading home on 11 over.
Both posted 75s on Friday. MacIntyre fought back with four birdies after dropping a scarcely believable eight shots in his opening four holes.
“That was carnage,” said the newly crowned Scottish Open champion. “When I made that eight on four, my head was completely gone. I didn’t think I was going to make the weekend, it was just about fighting and the fans helped me a long way.”
Like MacIntyre, McIlroy had a triple-bogey eight at the fourth and he was 13 over after the sixth as he failed to cope with the wind. Two late birdies in calmer conditions brought a rueful smile but his chase for a fifth major now extends beyond a decade.
“I didn’t adapt well and the wind got the better of me,” he simply said.
