Hamilton fired a 7-under 64 in the opening round at TPC Deere Run, an effort that left him one shot off the early pace and one that marked his lowest round on the PGA Tour since a 64 in the first round of the 2008 Frys.com Open.
Hamilton won the 2004 Open Championship at Royal Troon in a playoff over Ernie Els, but has posted just four top-10 finishes on the PGA Tour since. The 48-year-old has made only two of nine cuts this season on the Web.com Tour, with only one finish better than 70th, and this marks his first start this year on the main circuit.
A native of Galesburg, Ill., Hamilton has long been a crowd favorite in Silvis and is playing this week on a sponsor exemption. He showed no signs of his recent struggles during a bogey-free opening round, finding 16 of 18 greens in regulation while carding seven birdies, including three across his first five holes after starting on No. 10. At 7 under, he trails a trio of early leaders that includes 2012 John Deere champion Zach Johnson.
The round marked Hamilton's first sub-par effort on the PGA Tour since a third-round 70 at the Open Championship last year at Muirfield. His last top-10 finish came at the 2012 Reno-Tahoe Open, where he tied for eighth in an event that utilized a modified Stableford scoring system.