Tournament officials suspended the second round because of rain and darkness. The round will resume early Saturday morning, weather permitting.
Before play was halted, Estes and Armour -- co-leaders after Thursday's first round at 9-under-par 64 -- shot matching 5-under 68s to move to 14-under 132 through 36 holes.
"I've definitely been making some changes, different things at different times, trying to figure out what works best for me," said Estes, who has not won since 2002.
Estes and Armour lead runner-up Daniel Chopra (66), who is 13-under 133.
Sean O’Hair (68), Steve Lowery (66) and Michael Sim (67) share third place at 10-under 136.
When play resumes, the projected cut is even-par 146, which would mean Carl Petterson (146), Bob May (147), former PGA Championship winner Shaun Micheel (148) and Neal Lancaster (152) are done for this event.