The 18th proved to be a double-edged sword for the Irish as Graeme McDowell dramatically sank a 28 footer for a 67 to make the cut as Seamus Power double bogeyed for a 74 to slip eight shots behind leader Adam Hadwin in the Valspar Championship.
Afternoon starter Power was fifth overnight after a superb opening 66 but while he was off his game on Friday, he fought back from three-over-par at the turn to be just one-over for the day with one to play when he took six at the last.
The West Waterford star missed the fairway and the green, eventually finding the putting surface in four before two-putting for a three over 74 that relegated him to tied 32nd on two-under par.
It was a disappointing finish for Power, who also got off to a bad start and struggled to get control of his round until the back nine.
A bogey at the third was followed by another at the fifth, where he hit a poor wedge to 33 feet and three-putted.
While he birdied the sixth, he hit a bad drive at the seventh to hand that shot straight back, then drove into a fairway bunker and failed to get up and down from 48 yards for par at the ninth.
Out in 39, he knocked in a 25 footer for birdie at the 10th, then made a fine two from seven feet at the 15th to get within a shot of the top010.
He even made a good six footer for par at the 17th but undid much of his good work on the back nine with that closing double bogey.
McDowell, on the other hand, looked likely to miss the cut after his first round 75. But the Portrush native was far better from tee to green, missing just three fairways and only three greens as he posted a four-under par 67 to get back to even par.
The 2010 US Open champion opened up with three straight birdies, then recovered from a bogey at the sixth with birdies at the seventh, 14th and 15th before an untimely three-putt at the 17th left him needing a par at the last to dip under the projected cut mark.
Even though he hit the 18th green in two, he left himself a near 60 footer and ran it off the other side of the green before holing the return from nearly 30 feet for his four and a 67.
Leader Hadwin made eight birdies in a 64 to lead by a shot on 10-under-par from Herman, who followed his 62 with a 71.