San Francisco, Los Angeles and San Diego were potential cities for future NASL franchises, commissioner Bill Peterson said Tuesday.
"I know there are opportunities there, there are stadiums there, there are people who are interested," Peterson said. "We still have to go through the process of deciding if we have the right owners in the right locations, but we really don't have a West Coast presence."
The seven-team NASL will begin its third season with three games on Saturday.
Beginning this year, the league's regular season will be split into spring and fall schedules, with the winner of each half playing in the Soccer Bowl in November.
Peterson, the former president of NFL Europe, was selected NASL commissioner in November. He said he's excited about the possibility of adding three or four West Coast teams in the next two years.
"You look at L.A. County, there's 15 million people out there," Peterson said. "So when I look at it, I see a lot of opportunities in L.A. County and Orange County to put teams in there. And the great thing is, when you put more than one team in there, you get these great rivalries."
Peterson insisted the league's owners didn't feel pressure to expand within a certain time frame.
"The correct way to expand is to expand when ready, and our owners are very committed to that," he said.
The New York Cosmos will join the NASL for the fall. The Puerto Rico Islanders suspended play for this season but are expected to return next year. Indianapolis, Ottawa and Virginia are planned new teams for 2014.
The league's current teams are Atlanta, Carolina, Edmonton, Fort Lauderdale, Minnesota, San Antonio and Tampa Bay.