MLS seeks two expansion teams by 2011 - CBC
Garber made the announcement after the league's board of governors meeting in Toronto, site of Thursday's all-star game (CBC, CBCSports.ca, 7 p.m. ET).
Garber said cities that were reviewed in the meeting as possible expansion candidates include Montreal, Ottawa and Vancouver.
Atlanta, Las Vegas, Portland and St. Louis are also being considered, as is a second team in New York.
Garber did not say when an decision will be made as to which cities will be granted an expansion club.
But it's believed Montreal and Vancouver have a strong chance.
One name that has been bandied about as potential owner of a expansion club is George Gillett Jr., an American businessman who owns the Montreal Canadiens.
Victoria's Steve Nash, a two-time most valuable player in the NBA, is also interested in bringing an MLS team to Vancouver, where his younger brother, Martin, plays for the Whitecaps.
Thursday's announcement contradicts statements made by deputy commissioner Ivan Gazidis, who told reporters last week in Toronto that MLS was in no rush to add teams.
Launched in 1996, MLS has grown from a modest eight-team league that garnered little attention from the sports media to a 14-team operation in 2008 that features one of the most famous athletes on the planet — David Beckham.
Toronto FC, the first Canadian club in MLS, joined the league in 2007.
MLS will expand to 16 clubs with the addition of a team in Seattle in 2009 and Philadelphia in 2010.