Séamus Power endured a frustrating Saturday at the CJ Cup Byron Nelson in Texas as a level par 71 left him tied for 29th going into the final round.
The Waterford man had been as high as a tie for 12th after the second round following Friday's bogey-free 65.
But that momentum did not carry over into a third round where his fortunes fluctuated.
Power made up for an early bogey on the second with a birdie on the par-five fifth.
But back-to-back bogeys immediately followed on six and seven, dropping him back, although he regained a stroke with a birdie on nine.
The back nine was slightly more positive, although it began with a bogey on 11 that was quickly followed by a birdie.
Another bogey on the 15th set him back again but Power finished strong with back-to-back birdies on his last two holes.
That leaves him on the 11 under score he started the day with and he is 10 shots behind leader Si-Woo Kim whose overnight advantage was cut down from five strokes to just two by the chasing major winners Scottie Scheffler and Wyndham Clark. They are tied for second on 19 under after both carded 65s.
Kim recovered from a bad mid-round stretch to card a 68, managing six birdies along the way, while world number one Scheffler - a hometown favourite and the tournament's defending champion - only had one bogey on the par-three fourth. Clark's highlight was an eagle on the par-five ninth.
Stephan Jaeger, Sung-Jae Im and Tom Hoge are tied for fourth on 17 under, while Zachary Bauchou has sole possession of seventh one shot further back.
Jaeger enjoyed the day's best round with a 64. He opened with birdies on the first three holes and delivered another three-birdie stretch on Nos 12 to 14.
Five-time major winner Brooks Koepka is part of a four-way tie for eighth on 15 under.
Additional reporting: Reuters
