Sean Crocker

Crocker, a native of Zimbabwe who went to high school in Westlake Village, Calif., rolled in three straight birdies at 11, 12, and 13 at Sunnehanna Country Club to post a back-nine 32, and second-round 66. On top of a 67 on day one, Crocker sits at seven-under par and leads a trio of players by a stroke.

At six-under are Zach Seabolt of Winthrop University, Hunter Stewart of Vanderbilt, and Chase Koepka of South Florida.

Crocker's freshman year for the Trojans was stellar, as the young team reached the NCAA finals before falling to LSU. He got the calendar year started off nicely with a win at the AmateurGolf.com San Diego Amateur, where he shot a final-round 67 at Aviara Golf Club to beat his teammate Jonah Texeira by two. In collegiate events, Crocker tied for fourth at The Prestige at PGA West, placed fifth at the Southern Highlands Collegiate Masters, and took ninth at the NCAA West Regional.

Crocker's 66 didn't stand as the lowest score of the day, however, as three players posted five-under 65. Auburn's Michael Johnson, Ole Miss golfer Ben Wolcott, and East Tennessee State's Chris Hickman were low on Thursday, with Johnson's round shooting him into a tie for 13th place just three back of the lead.

Tied for fifth place are eight players at five-under par, including first-round leader Cody Proveaux of Clemson. The Leesville, S.C. native cooled off after an opening-round 64 gave him a one-shot lead. He did finish Thursday on a good note, though, birdieing the short par-4 18th to post one-over 71.

Other notable players in fifth place are recent Mexican International Amateur winner Claudio Correa of South Florida, 2014 U.S. Amateur Public Links runner-up Doug Ghim of Texas, and last year's Dixie Amateur champion Brandon Matthews of Temple University.