McIlroy after a near miss on the greens in his second round
Rory McIlroy remained in contention at the fog-affected USPGA Championship as his second-round 68 left him five under and three behind leader Matt Kuchar.
First-round leader Kuchar improved to eight under after a 69 which left him the clubhouse leader by one from fellow American Nick Whatney.
Dungannon's Darren Clarke shot a battling 70 to lie level par at halfway at Whistling Straits.
However, Graeme McDowell and Padraig Harrington missed the cut.
The second round was completed on Saturday with the cut at one over.
McDowell fired a second-round 71 but was it was not enough after his opening 76.
A double-bogey on the last hole Harrington left the Dubliner with a 71 and one shot outside the cut on two over.
After starting at the 10th, McIlroy produced a round of five birdies and a solitary bogey on the seventh.
An excellent up-and-down for par at the ninth followed a superb birdie at the eighth where he fired a superb second shot to 20 feet from an awkward stance in the rough and holed the putt.
McIlroy was content with his position at the halfway stage.
"I felt the last two putts gave me a good chance going into the weekend," said the 21-year-old.
"I already made two double bogeys in first round so I know how brutal the course can be.
"The key is to just keep the mistakes off the card and I was lucky I did that today.
"I think my chances are good, I'm only three behind and I feel as if I'm playing good golf."
Shane Lowry, after his promising opening 71, slipped back to six over after a disappointing 79.