Piercy would not play a shot from just off the 16th green, calling a rules official to say there was too much water between his ball and the hole.
After several minutes, chief official Mark Russell decided to halt competition, with deep puddles covering many parts of the course.
Three-times PGA Tour winner Johnson Wagner led at 15-under after 15 holes, one stroke ahead of fellow Americans Piercy (15 holes) and Patton Kizzire (16 holes), with Englishman Paul Casey (15 holes) two shots behind.
The 16 players who did not complete the round will resume early Sunday, with the final round still scheduled to be completed on time.
American Justin Thomas appeared to sum up the mood of the players with an expletive-laden rant about the conditions after missing a par putt at his final hole.
The borderline unplayable conditions were not the only thing Piercy had reason to complain about.
His seven-iron at the par-three 11th landed in the hole, but rather than celebrate an hole-in-one, he watched in dismay as the ball clattered against the flagstick and ricocheted 50 feet away.
The rebound cost him two shots, and he trudged off with a par instead of an ace.
(Reporting by Andrew Both in Cary, North Carolina; editing by Ian Ransom)
