Belgium’s Nicolas Colsaerts shot a three under par 68 to remain firmly in the hunt for the Frys.com Open.
The Ryder Cup star’s effort moved him to eight under par at CordeValle following a bogey-free opening 65.
That was good enough for a share of fourth place in California, five behind American leader John Mallinger.
Mallinger’s nine under par 62 took him three clear of compatriot Billy Horschel and Venezuelan Jhonattan Vegas.
Colsaerts started on the back nine and birdied three of his first four holes to catch overnight leader Nick O’Hern.
However, another gain at the 15th was sandwiched by bogeys at the 14th and 16th.
The front nine was more sedate, with a birdie at the seventh the only deviation from par.
O’Hern was level with Colsaerts after a 71, with England’s Greg Owen moving into the top ten with a 69.