Couples, trying at 53 to become the oldest winner of a major championship, was at 5 under on the front nine, a shot off the lead in the third round before calamity struck on the back nine.
Couples played the last five holes in 5 over to plummet to a tie for 18th going into Sunday.
“I would think that put me out of the running for anything tomorrow,” Couples said.
His day ended with back-to-back bogeys at the 14th and 15th and then a triple bogey after getting himself into the trees at the 17th.
“It was just a comedy of bad shots,” Couples said.
Couples seemed to feel as badly for his fellow competitor, Jason Day, as he did for himself at the 17th. In trying to figure out the best way to extricate himself from the woods, he asked Day to play first. Day shared the tournament lead before making a three-putt bogey at No. 17.
“I was killing him there,” Couples said. “It took me forever to figure out how to make a 7.”