Graeme McDowell failed to make the cut at the Canadian Open after carding a level-par 72 on Friday to finish three over at Oakville.
2010 US Open champion McDowell, who has struggled for form this season, needed a big improvement on his opening 75 to have any chance of making the weekend.
But his hopes were ended early on Friday as a bogey at his third hole was soon followed by a double bogey.
He fought back with four birdies but ended five shots outside the cut mark.
McDowell was 17 shots behind leader Chad Campbell, who holds a two-shot advantage on 14 under after a 63.
The 35-year-old Northern Irishman has struggled for form this year and has slipped from 15th to 58th in the world rankings.
His best PGA Tour finish in 2015 is a share of 26th place at the Heritage event in April and he has missed the cut in his last three events in the US.
McDowell also made an early exit at the French Open earlier this month after going into the Paris event as the twice defending champion.
The Portrush man finished joint 49th at The Open last week, 11 shots behind winner Zach Johnson.