Paul Casey shot a 68 to finish the third round of the Frys.com Open two shots adrift of leader Briny Baird, with Tiger Woods a further seven back.
Casey, on his way back from injury and looking for a second victory in 2011, played a flawless round featuring three birdies to move 11 under.
Woods, playing his first event since August, looked set to make a charge when he birdied the first two holes.
But a bogeyed third halted his momentum on the way to a 68.
However the former world number one, who has dropped out of the top 50 on the back of a run that saw him miss the cut at the US PGA in August, declared himself pleased with his progress as he carded consecutive sub-70 rounds for the first time since January.
"It's getting better," said Woods.
"I'm improving day by day, which is good. Tomorrow I need to improve a lot and make putts and post a really low one."
Those low scores appear to be available - both Jim Renner and Will Mackenzie carded nine-under-par 62s while Baird, chasing a first career title, shot a 64 that included a bogey at the last.
Casey, who is still recovering from a toe injury, decided to return to the PGA Tour for the next two weeks to complete the minimum 15 events required to maintain his card for next season.
The Englishman, the highest ranked player in the tournament, was joined in second by Ernie Els who moved to 11 under with an eagle at the par-five ninth but failed to improve over the back nine.