It was the 20th score of 60 or better in PGA Tour history. Perez, 29, is a former Nationwide Tour winner and has never won a PGA event.
Elsewhere on the opening day of the five-day event, Chad Campbell stands alone in second place at 9-under 63; Steve Elkington is third at 8-under 64; and John Huston, Olin Browne and Tom Pernice Jr. are tied for fourth place at 7-under 65.
This is the first event Mickelson has played in 2006.
The tournament is being played on three different courses.