NeSmith finished third after rounds of 69-68 while Knox shot 68-71 and finished in a three-way tie for the fourth and final spot. In a playoff, Knox beat Todd White and Jordan Byrd for the spot.
Augusta’s Dykes Harbin shot 72-68 and missed the playoff for the fourth spot by a shot.
Brian Carter, of Evans, tied for 15th place after rounds of 71-73.
The U.S. Amateur will be played Aug. 12-18 in Brookline, Mass., at The Country Club.