Tiger Woods endured a difficult return to action at the Frys.com Open, firing a double bogey at the 12th on his way to a two-over-par 73.
Woods, playing his first tournament in nearly two months, started the day with a birdie but managed only one more as he finished the day six shots back.
"That's probably one of the worst putting rounds I've ever had," said Woods, who could miss consecutive cuts for the first time as a professional.
"I can't putt any worse than today."
The former world number one has not played since failing to make the cut at the US PGA Championship in August, after suffering injuries to his left knee and left Achilles tendon.
However, his putting aside, he was relatively pleased with his play as he looks to halt a slump that has seen him drop out of the world's top 50 for the first time in almost 15 years and without a win since the 2009 Australian Masters.
"The rest of the game was not too bad," said Woods, who was partnered by new caddie Joe LaCava for the first time.
"I hit some bad shots, yes. But also, I hit some really good ones. I'm very pleased at the shots I was hitting most of the day.
"But I got nothing out of the round on the greens. And whatever momentum I could have gotten by hitting good shots - you know, I just missed putts."
As Woods struggled, Brandon Steele, Briny Baird, Garrett Willis and Matt Bettencourt enjoyed better days, firing rounds of 67 to share of the lead.
England's Paul Casey was the leading European, finishing on one under.