Morrison's candidacy, which comes four years after term limits forced him from office, potentially turns November's election into a referendum on theproposed ballpark-village development.
Morrison has been the most vocal critic of the $1.8 billion plan that would bring a baseball stadium, retail shops and up to 3,100 new homes to 226 acres next to the Pacific Commons Shopping Center.
The two other announced candidates, current Mayor Bob Wasserman and Councilmember Steve Cho, both support the plan.
The A's proposal will be a major issue, Morrison said, but it won't be the sole focus of his campaign.
He said the city has become too focused on generating sales tax revenue at the expense of quality of life for residents, and not proactive enough in dealing with crime and continued population growth.
He also criticized the council's handling of a stalled redevelopment project in Centerville and Measure L, the failed 2006 utility tax measure that Morrison said had poisonedfuture tax-increase efforts when the city announced a surprise budget surplus one month after voters rejected the tax.
"I'm just not happy, so I'm going to raise the issues on things I'm not happy about, and see if it strikes a chord," Morrison said.
He backed Wasserman in 2004, and his candidacy complicateswhat appeared to be a straightforward path to re-election for the mayor.
Wasserman already has secured endorsements from Fremont's political establishment and has raised more than $25,000 for the campaign.
Also, Wasserman, a centrist Democrat, could have expected strong support from liberal voters in a two-person race against Cho, the council's lone Republican.
Now, the mayor faces a challenge on the left from Morrison, who previously has depended on strong support from left-leaning Democrats and a challenge on the right from Cho, who also is expected to fare well among Chinese-Americans, Fremont's largest ethnic group.
Councilmember Bob Wieckowski, a long-standing Morrison supporter who also is up for re-election, said Morrison's entry into the race won't cause him to withdraw his endorsement of Wasserman. It will, however, keep him from actively campaigning for Wasserman, as he would have done had Cho been his only opponent.
"All I would be doing is hurting myself," he said of stumping hard for Wasserman.
Wasserman wouldn't say much about Morrison's candidacy, but said he was concerned that the A's development plans now will dominate the November election.
"I don't think we need that," he said. "Things have been going very well."
Morrison, 72, spent nearly a quarter-century on the council, including five terms as mayor. He was barred from seeking re-election in 2004 because of a city term-limits rule enacted in 1996 that prohibits lawmakers from serving more than eight consecutive years in the same seat.