'It's been a long day,' said Sorenstam. 'I don't know if I can call it a roller-coaster day, but it's been tough.'
Karrie Webb, Rachel Teske, Carin Koch and Candie Kung share fourth place at 5-under-par 211. Laura Diaz followed at 4-under-par 212 while defending champion Meg Mallon was seven shots back at 3-under-par 213.
Sorenstam, who had extended her lead to three strokes heading into the weekend, found trouble early at Trump International Golf Club with a bogey at the par-4 first. Sorenstam then missed the green at the par-3 fifth and failed to get up and down for another bogey.
The Swede, who is seeking her 56th career victory on the LPGA Tour, struggled at the par-3 11th despite finding the putting surface off the tee. Sorenstam three-putted for her third bogey of the day to fall back to 7 under.
Sorenstam responded at the par-4 13th and hit a 5-iron inside 6 feet for her first birdie. She then two-putted for a birdie at the par-5 15th to get to minus-9.
'The flow wasn't there,' she said. 'I tried to dig deep on the last few holes and made a few birdies.'
At the par-3 17th, Sorenstam dropped an 8-iron inside three feet and converted the short birdie putt to hold a slim lead with one round to play.
'Today I felt it was really tough for me,' said Sorenstam, who won this event in 1997 and 2002. 'I couldn't really play the front nine, and I'm just glad I liked the back nine, to come back and put a good score together, and at least put a decent score together.'
Rosales played her second shot to 2 feet for a birdie at the par-4 sixth and hit her tee shot within 6 feet of the hole for a birdie at the par-3 11th. She added a birdie at the par-4 14th for a round of 69.
'I'm not going to think about tomorrow,' said Rosales. 'I just have to play my game and hang in there until the last hole. I know Annika is always going to be there. I'm just going to play my game.'
Kerr picked up her first birdie of the day at the sixth and hit her tee shot to 10 feet for a birdie at the par-4 14th en route to a round of 70.
'I played well today,' said Kerr. 'I had some chances today that I could have converted on, but if you're putting for birdie a lot and tapping in for par, that's great on this golf course. That's what I've done.'
Grace Park, Lorie Kane and Jeong Jang are knotted in 10th place at 1-under-par 215.