To the casual observer, Bill Thompson dropped off the map following his narrow defeat to Mayor Michael Bloomberg in 2009.

He remained nearly invisible until last week when, seemingly out of nowhere, Thompson burst back into the 2013 mayoral field as a top contender after raking in $1 million in the latest filing period.

“It is completely different this week,” said one high-ranking City Council member, echoing powerbrokers across the city who sounded blindsided by the change. “The million-dollar filing changed the game.”

The influx of cash, which was more than any other mayoral candidate hauled in during the last six months, coincided with a surge of speaking engagements. He gave his first major policy address at a breakfast thrown by the Association for a Better New York, and at a debate in Harlem, Thompson drew enthusiastic cheers as he vowed to oust NYPD Police Commissioner Raymond Kelly as the city’s top cop.

READ MORE: DNA