Storms caused a delay of more than four hours at Oakland Hills
Thunderstorms forced play to be called off with only 25 of the 73 players having completed their third rounds in the USPGA at Oakland Hills.
More than four hours were lost and play was set to resume at 1215 BST on Sunday with the fourth round following on.
Leader JB Holmes (-1) and England's Justin Rose (level) were among six players still to start the third round.
Argentine Andres Romero shot 65 to reach to two over, while Steve Flesch climbed to one over after five holes.
Holmes remains the only man under par at one under, with a one-shot lead over Rose, American Ben Curtis and South Korea's Charlie Wi.
Swede Henrik Stenson and American David Toms are one over, while one further back are Argentine Angel Cabrera and American Brandt Snedeker, who teed off on the 1st before the hooter called a halt.
Yesterday I was very mad with my round  - today, I can't believe it
"It's going to be like college again, playing 36 in one day," said the 26-year-old Holmes. "It happens, and everybody else is going to do it, too, so just have to go out there and deal with it.
"And they've got 12 hours to work on the golf course. It needed the rain."
Romero's round, which equalled the competitive course record at Oakland Hills, included seven birdies and two bogeys and came under sunny skies in easier scoring conditions to those seen on the first two days.
"I played an excellent round," said the 27-year-old, who came third in the 2007 Open at Carnoustie "It was almost perfect.
"Yesterday I was very mad with my round . Today, I can't believe it. I can't believe I'm here."
Flesch picked up two birdies inside his first four holes, while Colombia's Camilo Villegas picked up four shots in 14 holes to reach two over.
American Boo Weekley also climbed one shot to two over par after four holes to join the group that also includes Sergio Garcia and Aaron Baddeley.
Northern Ireland's Graeme McDowell, Thailand's Prayad Marksaeng and Swede Fredrik Jacobson were all three under for the day nearing the end of their rounds and three over for the tournament.
South Africans Ernie Els and Retief Goosen were both one under for the day after 13 holes and five over overall, the same score as Scotland's Alastair Forsyth and England's Ian Poulter, who were both level through nine holes.
Double Open champion Padraig Harrington carded two bogeys and two birdies in his first eight holes and was also five over.
England's Paul Casey, who said after the second round that anyone making the cut still had a chance to win because of the severity of the course, slipped back to eight over after 14 holes.
The final round, which will be played in threesomes going off from both the 1st and the 10th, is scheduled to begin at 1720 BST.
The last major champion to play 36 holes on the final day was Seve Ballesteros in the 1979 Open, while Tiger Woods played 27 holes on the Sunday when he won the rain-delayed Masters in 2005.