SPRINGFIELD, Mo. -- Colt Knost, the reigning U.S. Amateur champion, could have been playing in the British Open this week in England. Knost also would have gotten exemptions into the Masters and the U.S. Open, but the Dallas, Tex., resident decided to turn professional last fall after a stellar amateur career that also included a win at the U.S. Amateur Public Links Championship.

By turning pro, Knost lost his exemptions. They were for amateurs only. But at his current pace, the former SMU Mustang might get a shot at the majors as early as next year.

Knost, the first-day leader after an 8-under 64, added a 5-under 67 Friday at Highland Springs Country Club to maintain his lead after two rounds at the Price Cutter Charity Championship. The 23-year-old Nationwide Tour rookie already has one victory on his resume this year -- the Fort Smith Classic -- and a second would all but assure him one of the 25 PGA TOUR cards that will go to this season's top money-winners.

"I don't worry about things like that. I'm focused on this," said Knost of his decision. "This is a major to me this week. Every tournament is."

With much of the golfing world focused on the likes of Greg Norman, Rocco Mediate and David Duval at Royal Birkdale, Knost is calmly going about his business of joining the big boys in 2009. His 13-under 131 total put him two strokes in front of Darron Stiles (65), Brent Delahoussaye (63) and New Zealand's Bradley Iles (65).

Three shots back are Arjun Atwal (68), Spencer Levin (67), Vance Veazey (68), former champion Roger Tambellini (65), James Love (67) and recent Wake Forest grad Webb Simpson (68), who is making his first Nationwide Tour start.

"I know that one good week puts me on the PGA TOUR next year," said Knost, who is No. 20 on the money list and could jump to No. 3 with a Sunday payday of $108,000. "I don't really have to make that much money to get it done but it's out there and you still have to do it. That's the hardest part."

Everything has been fairly easy thus far for Knost, whose bogey on the second hole Thursday was his only hiccup through 36 holes. His 14 birdies are tied for second most at this point.

"I've been hitting a lot of good iron shots. I'm hitting a lot of shots close and make the putts you're supposed to make," said Knost, who is 30 of 36 in greens in regulation. "It seems like I've been having really good numbers and hitting full shots in there. I'm only half done though. I'm glad to have a chance going into the weekend."

Among those chasing him is Stiles, an unofficial winner earlier this year in New Zealand and No. 5 on the year-to-date money list. Stiles, a Pinehurst, N.C., resident, has already secured a place on TOUR next year and is now able to relax a little as the season heads to November close in Dallas.

"I'm relaxed to the point that I just want to go out and play solid golf. I'm not having to worry about week to week and what I need to do to get into the top 25," said Stiles after seven birdies and an eagle during Friday's play. "That's definitely helped, but there is still stuff I want to accomplish. The sole focus is to get to No. 1 because of the full exemption and getting into THE PLAYERS Championship."

While Knost and Stiles are in familiar surroundings, Delahoussaye and Iles are looking for a big weekend to change their fortunes. Delahoussaye, a 2005 Clemson grad, had made only three cuts in his previous 11 starts and is No. 156 on the money list. Iles, a 24-year old rookie, had made only four in 11 starts and is only slightly better at No. 146.

"These guys are so good out here that anybody can shoot anything," said Delahoussaye after a bogey-free round of 63. "I went out there with the mindset of 'who cares, just go out and play well and see what you can do.'"

Second-Round Notes: Craig Lile (finger), Mike Heinen (neck) and David Morland IV (wrist) all withdrew during the round due to injury. ... Second-round leaders have gone on to win this tournament four times in 17 years, with Tom Scherrer (2007) and Brad Ott (2004) being the most recent. ... Tyler Williamson had two eagles in a four-hole stretch. Williamson eagled the par-5, 11th hole and then the 427-yard, par-4, 14th hole. Williamson is the course record holder, thanks a final-round 12-under-par 60 in 2004. ... A total of 67 players made the 36-hole cut, which came at 5-under 139. The 5-under cut matches the lowest on Tour this year, at the Ford Wayne Gretzky Classic. ... The lowest cut in tournament history was 6 under par in 2006. ... The second-round scoring average was 70.364.