Garrett Willis, Bob Tway, Frank Lickliter and Matt Peterson are all just one stroke back of Roberts at 12-under.
Second round co-leader Pat Perez and Andrew Magee are both two off the pace at 11-under after shooting rounds of 69 and 68, respectively.
Fan favorites and forty-somethings Fred Couples and Fred Funk both enjoyed great rounds and find themselves only three strokes behind the leader Roberts.
Roberts, whose last victory came at the 2000 Greater Milwaukee Open, followed up his superb Friday 63 with a low key 67.
One behind the leaders coming into the 17th, Roberts knocked a 5-iron to five feet of the pin and rolled in the birdie to get to 12-under.
His approach from the rough at 18 was to in six feet and the subsequent birdie was the final margin. On the day Roberts had five birdies and two bogeys.
'It was a very good way to end it,' said Roberts. 'Today is Saturday, you want to keep yourself in position to have a chance tomorrow. I'm right there for tomorrow. Today is positioning day. You can't win it today, but you can sure lose it.'
Willis, who shot a course record 61 on Friday, held the lead at 14-under before stumbling home with bogeys on the final two holes. His finish the round with a 4-under 66.
'Today doesn't have any relevance,' said Willis. 'Yesterday doesn't have any relevance on today, other than the fact I've put myself in contention.'
Lickliter had nine birdies in his round, including an amazing run in which he carded eight in an 11-hole stretch. A couple of costly double bogeys kept him from owning the outright lead.
Tway and Peterson shared similar rounds, each carding five birdies and a double bogey to finish with 67s.
Full-field scores from the Velaro Texas Open