Garrison, who plays for the University of Tennessee, had just his second bogey of the tournament at No. 9. He made an eagle at the par-5 13th. Last week, he finished T-39 at the Southern Amateur.
Austin Rose, of Mississippi State, eagled the 18th hole to get to 5-under 67 for the day. He is solo third at 7 under.
Two golfers are tied for fourth at 6 under, including Jordan Hahn of the University of Wisconsin and Ben Rebne of Dalton State College. Rebne started the day in second and one off the pace but lost ground with two bogeys and a double sprinkled throughout his round.
The top 17 players are all under par entering the final two rounds.
