Action was delayed for two hours in the morning due to rain and 72 golfers were on the course when it was halted due to darkness. The round will resume Friday at 8:30 a.m. EDT.
The 43-year-old Couples has 14 titles on the PGA Tour but is winless since capturing the Bob Hope Classic and The Memorial in 1998.
"I haven't been in any kind of contention for three or four years," Couples said. "So for anyone telling you it's like riding a bike, it's not like riding a bike."
Starting on the back nine, Couples made eight birdies.
"I haven't been putting well, which is something you have to do," said Couples, who tied for 28th earlier this month at the Masters, a tournament he won in 1992.
In addition to a 30-footer for birdie, Couples had four putts from 15 feet. He has finished 13th or better in four of his last five starts, including a seventh-place showing at the Nissan Open.