Furyk, who shared the first-round lead with Steve Stricker, shot a four-under 67 Saturday to match O'Hair, who had a 64 Saturday at 12-under-par 130 after 36 holes.
World No. 1 Tiger Woods, the 2006 champion, shot 67 to move into a share of 28th at 137.
"I had to make them," Woods said of making clutch par saves on nine and 11. "I didn't have much of a choice. I was right on the cut line and 11 back at the time. I wanted to play the last seven holes in five-or six-under par to get back in the ballgame."