"I just got a little burnt out in college and needed some time to myself," she said of her lengthy hiatus. "Ever since I was 13, I've been doing everything for golf, golf, golf. I never really had time to enjoy friends and family how you would want to. So that's what I did for a year and a half, two years, and started to get back on track."
Arimura, fourth in the LPGA's rookie standings, three-putted the final hole for bogey and a 68.
Jennifer Johnson (66), Chella Choi (66) and Jodi Ewart Shadoff (68) were at 205.
Park has been the talk of the tour this year, with six victories including wins in all three of the major championships. She'll go for four in a row when the tour returns to action in two weeks at the Women's British Open at St. Andrew's.
But after winning three in a row and with a solid finish last week, she sagged to a 73 that left her tied for 23rd. She double-bogeyed the first hole after hitting her drive into a fairway bunker and never recovered.
That wasn't the worst of it.
"I just putted really bad today," she said, after dropping from sole possession of fifth place through 36 holes. "Outside of that, everything else was really similar (to earlier rounds of 67 and 69), but nothing seems to be going in."
Ryu, who shot a 62 in the final round to win a year ago by seven strokes, shot a 70 and was six shots back of the leaders. Ko became the youngest LPGA winner ever when she took the Canadian Women's Open last year at 15, but she had a 71 and was tied with Ryu at 207.
Alison Walshe, tied with Recari and Creamer after the second round, fell back with a 73.
Creamer said that she'll try not to concentrate only on her version of match play with Ricari.
"You can get hot out here and shoot a low number, so I can't worry too much about what she's doing," she said. "I've got to go out and play my own game because there are going to be a lot of players that can fire at pins and post a low score. I'll just have to make as many birdies as I can."