Jay DeMerit will announce his retirement on Thursday at a press conference in Vancouver, a team source confirmed to CBC News.
DeMerit, who took in the Pemberton Music Festival over the weekend, began speaking to the team about his impending retirement last week.
Injuries may have played a key role in the decision for the 34-year-old. DeMerit suffered a torn tendon in his left knee in a 3-3 draw with the Philadelphia Union on June 12. He was expected to miss six-to-eight weeks.
He and also tore his Achilles tendon in 2013.
With DeMerit retiring, the Whitecaps would save $100,000 toward their salary cap.
DeMerit spent four years with the Whitecaps and started 11 games this season.
DeMerit was the first player the Whitecaps signed in 2010 when Vancouver was preparing to enter Major League Soccer.
He had played for Watford of the English Premier League for six seasons before joining the Whitecaps.
The Green Bay, Wisc., native played 25 games with the United States, including starting four games for the Americans in the 2010 World Cup.