Shane Lowry's hopes of extending his season in the FedEx Cup lie in the balance after a disappointing level-par 70 at the Wyndham Championship in North Carolina.
The Offaly golfer is likely to require a finish close to the top 20, but will start the final round just outside the top 50 as he couldn’t improve on his two-under score.
Lowry started with four straight pars before picking up his first shot of the day at the par-five fifth after reaching the green in two, but he found water at the seventh to give that shot back.
The back nine started in disappointing fashion with bogeys at 10 and 11, the latter after finding the left rough off the tee, but a beautiful approach to six feet on the 13th saw Lowry claim his second birdie of the day.
Lowry moved to four-under with a brilliant eagle on the 15th, knocking his second to 13 feet from 230 yards, but it was followed by a bogey to leave him on three under for the tournament.
At the summit, Lucas Glover shot an eight-under 62 and Billy Horschel also flourished with a 63.
They both lead the way on 18 under, with second-round leader Russell Henley one shot further back in third place after shooting 65.
South Korea's Byeong Hun An is three shots back in fourth after a 65 and Germany's Stephan Jaeger (64) is fifth on 13 under.
Glover had nine birdies and one bogey during his round. Horschel had seven birdies during a bogey-free round. Henley had six birdies and one bogey.
Michael Kim also shot a blistering 62 and is along in sixth place, seven shots behind the co-leaders.
Additional reporting: Reuters
