When she had similar pain a decade ago, she was out of action for about eight months.
But Pettersen missed only a month this time, and the 33-year-old Norwegian is already on top of the leaderboard again after a bogey-free 5-under 66 on Thursday in the first round of the North Texas LPGA Shootout.
''I feel good. I mean very patient. Just really just trying to enjoy being back,'' Pettersen said. ''I got to kind of pace myself a little bit. I can't do too much early in the week. So I have a lot of spare time to fool around with. ... I really can't go hit balls on the range. I play whatever I need to play and then just try to give my body a little bit of break.''
Pettersen is playing her second tournament since withdrawing before the Kia Classic in late March, and being told rest was the way to heal her back. The world's fourth-ranked player tied for 28th in San Francisco last week.
''It's been a little bit achy early this week. So taking it a little bit careful,'' she said. ''But last week was nice to be back. It's always tough when you come back from something like that when you're so out of play. You're not even close to be playing. And then next thing you know the pain is gone and you can start hitting balls, and to bring back the mentality straightaway.''
Pettersen took sole possession of the lead when she birdied Nos. 7 and 8, her 16th and 17th holes of the day at Las Colinas Country Club.
Among the 35 players under par was Juli Inkster, the 53-year-old with eight major victories who shot 69. The last of Inkster's 31 career victories came in 2006.
Wie is playing with confidence and just trying to have fun, and had her 15th consecutive round of par or better. All have come in a stretch when she was the runner-up in the season's first major, won at home in Hawaii for his first LPGA victory in nearly four years and then had another top-10 finish last week in San Francisco, not far from alma mater Stanford.
''Definitely, my confidence level is up from last year, '' said Wie, whose five top-10 finishes are already one more than she had in 26 tournaments all last season.
Park had four birdies, but the South Korean also had a bogey at the par-5 third hole, and made double bogey at the par-4 15th.
''It was just one of those kind of days,'' Park said. ''Nothing went really wrong, but just a couple of bad shots that really penalized me today.''
Lewis' round included two three-putts and a one-stroke penalty when she unintentionally kicked her own ball in the No. 10 fairway.
Kim hit 17 of 18 greens, while needing 31 putts in a bogey-free round that was her lowest score this season. The 30-year-old hasn't won an LPGA event since 2005, and her best finish last season was tying for 11th at North Texas.
''Just played steady,'' Kim said. ''I struck the ball really well and just kept the ball in front of me and was able to find it after every swing.''
Masson started the inaugural North Texas LPGA Shootout last year with a bogey-free 64, and the German also was the second-round leader.
''On one hand I know I can go low here and shoot a good score. On the other hand, I kind of feel like I want to make up for the last round last year,'' said Masson, who finished 15th last year after a closing 75. ''It's positive memories, though. I mean it was a great week for me last year, just to really get going. ... It's never nice to shoot a bad last round, but I don't have it in my head too much.''