Dustin Johnson, Justin Thomas among co-leaders at Masters

AUGUSTA, Ga. — The buzz was back Friday at Augusta National, loud as ever.

It wasn’t from any of the patrons because they’re not allowed in this most usual Masters in November. It came from the constant humming of motors of the sub-air system beneath the soft turf in an attempt to make the course a little firmer, a lot more like a typical Masters in April.

“You have to really throw all the past knowledge out the window this week, as weird as it is,” said Justin Thomas, who hit a few short-game shots that required trust and imagination for rounds of 66-69.

That gave Thomas a share of the lead with Dustin Johnson (65-70), Cameron Smith (67-68) and Abraham Ancer (68-67), a Masters rookie who doesn’t know this course any other way.

“A lot of the history and things that you know about the golf course, it can sometimes hurt you this week because of what you’re used to,“ Thomas said. “But at the end of the day, it is a lot softer and a lot more scorable.”

Progress could be measured in greens that began to pick up some pace and scoring that didn’t get out of control.

Johnson, looking every bit like the No. 1 player in the world, had four birdies on the back nine in the morning for a 65, breaking by two shots his best round at Augusta. He birdied his way through Amen Corner at the start of his second round and quickly reached 10-under.

Johnson was slowed by a three-putt bogey on the 14th and a 3-iron that caught enough of a gust to come up short on the par-5 15th and roll back into the water, leading to another bogey.

He finished with a birdie for a 70 and was atop the leaderboard with the others at 9-under 135 when the second round was halted by darkness, a product of a weather delay at the start of the tournament that has put the Masters behind...