GREENSBORO, N.C. (AP) - Jimmy Walker didn't go to the U.S. Open. Instead, he went to the doctor.
Now that his knee is feeling better, he's in a good spot to contend for his first PGA Tour victory.
Walker shot an 8-under 62 on Friday to take the lead at 12-under 128 after two rounds in the Wyndham Championship.
Defending champion Webb Simpson (63) was one stroke back. First-round leader Carl Pettersson (68), Tim Clark (67), Sergio Garcia (63) and rookie Harris English (64) were at 10 under.
Tim Herron matched the tournament record with a 61, but was still nine strokes back.
Play was halted for 1 hour, 17 minutes late in the day when a system of thunderstorms passed through the central North Carolina Triad.
Walker, a 33-year-old Texan who finished in the top 10 in three of his first six tournaments, tore his left meniscus earlier this year. He skipped the U.S. Open and instead got a cortisone shot to reduce the swelling.
``There for a while, I was out of my routine because I couldn't bend down, I couldn't read putts the way I wanted to,'' Walker said. ``I got that fixed and started feeling pretty good about everything again, and, you know, all the stuff I had been working on (was) starting to pay off.''
He began the day four strokes back, had eight birdies in compiling one of the best two-day scores in event history. Only Pettersson at 125 in 2008 was better than Walker through 36 holes at Sedgefield Country Club.
``I was playing with J.B. (Holmes), and he was bombing the driver everywhere, and I was just kind of bunting the 5-wood around and hitting good approach shots,'' Walker said. ``It was pretty boring-looking golf - not a lot of drivers, not a lot of 3-woods. There's a lot of 5-woods and some irons, and it's just kind of placement around the golf course.''
And now that he can bend down and read greens again, he can do some damage with his putter. He used it just 26 times Friday, and didn't even need it on No. 2 because he chipped in from 50 feet.
``If it wouldn't have gone in, it probably would have rolled over the back of the green,'' he said.
Pettersson, who shot a 62 on Thursday while playing in the morning, found his familiar Sedgefield course to play tougher in the afternoon. The Raleigh resident and member of the country club's board of directors had two bogeys in a three-hole span midway his round, then came on strong with consecutive birdies on Nos. 9-10 and an eagle on the par-5 15th.
He broke his driver on the next-to-last hole of the first round, used his backup driver Friday and will stick with it the rest of the weekend.
``I struggled today,'' Pettersson said. ``Didn't have much today, but I thought it was a good comeback. ... Two-under par was OK for the game that I had, and hopefully I can hit the ball better on the weekend and have a chance.''
Simpson, a native North Carolinian and U.S. Open champ who's defending a title for the first time in his career, got hot on the back nine with birdies on four of his final five holes to rocket up the leaderboard.
``To play a round on a golf course this tricky without a bogey is always a good thing,'' Simpson said.
Herron rebounded after an opening 76. He became the fourth player in five years here to shoot a 61 and the first since Kevin Na in 2010.
``I didn't really have anything to lose,'' Herron said. ``I kind of zoned in a little bit today and just kind of kept rolling and making putts.''
It might have been just the strong round he needed to secure himself a spot in the FedEx Cup playoffs. Herron arrived at No. 133 on the points list and has to crack the top 125 to qualify for The Barclays next week.
The field is littered with players trying to prolong their seasons for at least one more week. Among those on the borderline who made it to the weekend were No. 122 Trevor Immelman, No. 129 Y.E. Yang and No. 133 Chez Reavie.
No. 126 Brendan Steele appeared to be in trouble before a run of four straight birdies pushed him to 3 under.
For others, there was bubble trouble. No. 121 Boo Weekley and No. 125 Jhonattan Vegas missed the cut of 1 under.