The proposed site at Victory Square would hold a 39,000-seat stadium just a few blocks south of Jack London Square along the city's waterfront. And if Oakland doesn't start an environmental study soon, it could lose its opportunity to keep the team.
"We'd be out of the running," City Council President Jane Brunner said.
The A's have played at the Oakland Coliseum since they moved from Kansas City in 1968.
Some people are calling the study a futile attempt by Oakland when MLB hasn't made a commitment.
If the stadium is built, nearby development could include up to 180,000-square-feet of retail, 540,000-square-feet of office space and up to 700 residential units.
The council's community and economic development committee voted 3-1 last week in favor of conducting the study. Councilman Ignacio De La Fuente was the only vote against it.
Bay City News contributed to this report.