David Toms, the 2001 PGA champion, was taken to a Pittsburgh hospital for tests and observation after falling ill on his 10th hole. Toms, who was even par before withdrawing, was in critical condition, according to doctors.
The 11-time winner is scheduled to represent the United States next week at The Presidents Cup. He is fourth on the money list this season.
Micheel began his round on the back nine at Nemacolin's Mystic Rock Course and moved to 2 under with an eagle at the par-5 11th. He bogeyed the next, but made the turn at minus-4 after posting three straight birdies from 15.
The 2003 PGA champion continued his scorching round with three consecutive birdies beginning at No. 1, which tied him with the clubhouse leaders at 7 under. Micheel then moved to minus-10 with an eagle at the par-5 fifth and a birdie at the sixth.
On pace to easily beat his best round of the year, the 36-year-old stumbled in a major way down the stretch with three straight bogeys to finish the day. But he still bettered his low 2005 round by two strokes.
The dropped shot at No. 8 was perhaps the most disheartening.
'Obviously I'm disappointed with what happened on the eighth hole,' Micheel said of missing a 4-foot putt at the par-5. 'I think I just lost my concentration a little bit.'
Micheel's best finish this season is a tie for seventh place at the Western Open in July. He hasn't won since collecting his maiden victory at the 2003 PGA Championship.
'I saw some good things,' he said of his round. 'The way my year has gone, I should be happy with 65. I played really well.'
O'Meara reached 7 under with eight birdies and a bogey, including six straight birdies from the fifth hole. The 16-time PGA Tour winner and two-time major champion needed just 21 putts to make it through his best round of 2005.
'It was by far the best putting round that I've had in a couple of years,' said the 48-year-old O'Meara, whose best finish this year is a tie for 27th at Byron Nelson Championship.
'Golf is a funny game and today seemed to go my way, so it was nice to get off to a good start.'
Among the leaders, only Gore's round was bogey-free. His day included four birdies on the back nine -- his first nine -- and three on the front.
The 31-year-old, who earned fan-favorite status by playing in the final group at the U.S. Open, is still enjoying the reaction he gets from the gallery since earning a 'battlefield promotion' from the Nationwide Tour last month.
'They were pretty great,' Gore acknowledged afterwards. 'A couple people would yell, and you're like, 'Gosh, I'm like 5 feet away, you don't have to yell.'
'I'll tell you what, the fans have been pretty awesome. It's kind of a really cool thing to see people get in your corner and root for you. It's a pretty special thing that they do for me.'
The fans may have a new underdog to root for on Sunday if Wi continues his strong play. The 33-year-old PGA Tour rookie had four birdies on both the front and back nine, and just one bogey at the par-4 15th.
Wi, who played in Asia and Europe last year, hasn't finished higher than 22nd in his first year on the PGA Tour.
'I know that everyone goes through the process, and I thought I had enough experience playing overseas, but that's part of golf,' he said. 'And I know that in time, everything is going to come together.'
Stuart Appleby, Ben Crane, Zach Johnson and Bob Burns share sixth place at minus-5, while six players are tied for 10th one stroke further back.
All in all, there are 32 players within five strokes of the leaders after the first round.