The 34-year-old underwent an MRI in Bristol, Connecticut, this week to further diagnose the injury he suffered during the first half of last Saturday's 3-3 draw at Philadelphia Union - Vancouver's final game before the current World Cup break.
The center back, who was a member of the 2010 United States World Cup squad in South Africa, has opted for non-surgery rehabilitation on the injury.
It is another setback for DeMerit, who missed most of last season with a torn left Achilles tendon - an injury he suffered in the opening minutes of the 'Caps 2013 season-opening win over Toronto FC at BC Place.
As a result of his injury diagnosis, DeMerit will likely miss Vancouver's next six MLS matches, at the very least, starting with its first game back from the World Cup break - a June 25th home clash versus Canadian rivals Montreal Impact.
With DeMerit sidelined, head coach Carl Robinson has four centre backs at his disposal in Andy O’Brien, Johnny Leveron, Carlyle Mitchell, and Christian Dean.
However, there is the likelihood that the former Wales international will look to strengthen at the center back position in the summer transfer window.