Craig Barlow flew up the leaderboard with a 5-under 65, that included a hole-in-one on the back nine, to move into a share of second place. He was joined at 5-under-par 205 by Jesper Parnevik (67). Ryan Moore, the 2004 NCAA champion, posted a 3-under 67 and is alone in fourth at minus-4.
He was joined there by Brian Davis, Jerry Kelly and Stephen Ames. Ames posted the low round of the week with a 6-under 64.
Calcavecchia opened the round with a five-stroke cushion and it remained that way for most of the front nine. He parred his first eight holes at Shaughnessy Golf & Country Club to remain at minus-8.
The 45-year-old tripped to a three-putt bogey on the par-4 ninth. Calcavecchia stumbled to another bogey on the 10 as his lead began to slip away. However, the 1989 British Open champion closed with eight more pars to remain at minus-6.
'I am excited about tomorrow. I didn't hit my driver quite as well today, but I made no birdies and I'm in half a state of shock about that,' said Calcavecchia, whose last tour win came at the 2001 Phoenix Open. 'That just never happens to me. I can usually scrape one or two in somewhere. The good news is I hit a lot of good putts. I just didn't read them right or my speed wasn't right or a combination of both.'
That string on the back nine was severely tested at the 13th hole. His drive found the left trees and he pitched into the adjoining fairway. Calcavecchia flew a wedge over the trees on to the putting surface. He rolled in the 18-footer to save par.
Barlow posted back-to-back, even-par 70s in the first two rounds. He started the third round with a bogey on the first and tripped to another on No. 2. After a par on the third, Barlow got one stroke back with a birdie at the par-4 fourth.
The 33-year-old climbed back to even par for the tournament when he birdied the par-5 seventh. Barlow moved into red figures with a birdie on nine, but he stumbled to his third bogey of the day at the 13th.
Barlow eagled the short par-4 14th to jump to minus-2. He then birdied the par-5 15th. After a par on 16, Barlow aced the par-3 17th to move into second place at minus-5.
'It was obviously a good day. I started off terrible,' Barlow said. 'On 17, obviously I hit a perfect shot. I'm thrilled to death it went in. When it left the club I knew it was going to be a good shot.'
Parnevik posted a 5-over 40 on the back nine of his second round to fall to minus-2 for the tournament. His struggles continued early Saturday as he bogeyed one, three and five to slide to plus-1.
The Swede began to fight back into the thick of things with birdies on six and seven. Parnevik parred three straight holes around the turn, then birdied the par-4 11th to move to minus-2.
Parnevik picked up another birdie on the par-4 13th. After parring 14, the 40-year-old eagled the par-5 15th to get to minus-5. He parred his final three holes to remain there.
Carlos Franco and Bob Heintz share ninth place at 2-under-par 208. They have carded matching rounds of 68-70-70 through three rounds. Michael Harris, Kevin Na and Trevor Immelman are the final players in red figures at minus-1.