Offaly golfer carded a round of 70 on day one of the RBC Heritage on the PGA Tour.
Shane Lowry will resume from one-under-par on day two of the RBC Heritage at Hilton Head in South Carolina.
The 2019 Open champion registered two birdies on the way in after picking up one bogey on the front nine
Viktor Hovland is the leader on seven-under, with Seamus Power well back on six-over.
In Hawaii, Stephanie Meadow in one-over-par following her second round at the Lotte Championship on the LPGA Tour.
She is nine shots behind joint leaders Yu Jin Sing and Natthakritta Vongtaveelap.