The 34-year-old Rocha, searching for his maiden US PGA Tour win, produced seven birdies and an eagle, the latter worth five points, while making three bogeys to sit on 24 at the halfway stage.
Americans J.J Henry and John Mallinger were tied in second place on 22 points - the former boosted by an eagle on the par-five eighth.
That hole proved to be a turning point for the Fort Worth-based Henry, who had opened his round with back-to-back bogeys.
"I think I was still asleep for those first two holes in the morning but actually I hit good drives and it was a couple of shaky approach shots that led to two bogeys, but I knew coming into this week that I was playing really well," Henry said.
Mallinger said he believed the scoring system was assisting his game.
"This is a new format for me, I've never played it before and I'm just trying to get used to getting the score out of my mind and just playing golf. I think it's actually helped me," he said.
Overnight leader Andres Romero of Argentina remained in the hunt, three points behind Rocha, despite five bogeys on Friday.
Florida-based Indian Arjun Atwal was level with Romero, after making 14 points in a second round containing nine birdies, although a double-bogey on the third scythed three points off his total.
Two-times Major winner John Daly was five points off the lead.
- John Mallinger