Graeme McDowell is nine off the clubhouse pace after carding an opening two-over-par 74 at the Canadian Open in Ontario.
McDowell, who has slipped to 101st in the world rankings and did not earn a place at last week's Open Championship, carded two birdies and bogeys.
After starting at the 10th, McDowell reached the turn in level par before dropping shots at the fifth and sixth.
Ireland's Shane Lowry is four off the pace at Glen Abbey after an opening 69.
Americans Hudson Swafford and Brandon Hagy lead in the clubhouse after rounds of 65.
The duo are a stroke ahead of a large group which includes former Masters champion Bubba Watson.
McDowell is 119th in the PGA Tour's Fedex Cup standings.