CROMWELL, Conn. — Brian Harman shot a 4-under 66 on Friday to move to 10-under par and watched that hold up for the second-round lead in the Travelers Championship, thanks in part to a 10-second rule.

Harman finished a stroke ahead of Matt Jones and first round co-leader Zach Johnson, who lost a stroke during his round of 68 when his birdie putt hung on the lip of the cup at the third hole for longer than the maximum allowed 10 seconds before falling in, giving him a par.

“After 10 seconds, the ball was moving and at that point even if the ball is moving, It’s deemed to be at rest, because it’s on the lip,” Johnson said. “Don’t ask me why, but that’s just the way it is.”

Harman had his short game working for the second consecutive day, taking 26 putts after needing only 23 during the first round.

“The putter has been really good so far, but I’ve been in position a lot,” he said. “I’ve had a lot of good looks at it. I’m just able to put a little pressure on the course right now, which is nice.”

Jones hit 16 of 18 greens for the second consecutive day, following up his first round 65 with a 66.

Bryson DeChambeau (66), Paul Casey (67) and Russell Henley (65) were two strokes back going into the weekend.

But Johnson, who started on the 10th tee, had the day’s most interesting round, which included just two birdies, but one amazing par save. He hit the ball into the TPC River Highland’s signature lake on No. 17, dropped across the water near the 16th tee box and then put his third shot within 8 feet of the hole from 234 yards away.

“You can’t hit that shot and then not make that putt,” he said.

Lanto Griffin and two-time Travelers champion Bubba Watson were at even par coming into Friday. But both shot a 63 to move into contention heading into the weekend, three shots behind the leader.