In the ever-shifting landscape of the New York City mayoral race, Public Advocate Bill de Blasio has moved into first place with 30 percent of the Democratic primary vote, according to a new poll released Tuesday by Quinnipiac University.

City Council Speaker Christine Quinn, long the presumed frontrunner, is in second place with 24 percent, followed by 22 percent for former Comptroller William Thompson. Scandal-plagued ex-Rep. Anthony Weiner is in fourth place with 10 percent. Comptroller John Liu is next with 6 percent; former Councilman Sal Albanese is in last place at 1 percent. Seven percent of voters are undecided.

The primary vote is set for Sept. 10. The New York City mayoral election to succeed Michael Bloomberg will take place Nov. 5.

In the likely event of a runoff, which would occur if no candidate captures 40 percent of the primary vote, de Blasio would beat Quinn 54 percent to 38 percent. De Blasio would also win against Thompson 50 percent to 41 percent. The city public advocate would also best Weiner, 72 percent to 22 percent.

"A few weeks ago, Public Advocate Bill de Blasio looked like an also-ran. Today, he's the leader of the pack, and a winner in the runoffs. Follow the bouncing ball, folks. This line-up keeps changing," said Maurice Carroll, director of the Quinnipiac University Polling Institute.

According to CNN, a Quinnipiac poll released last month had Quinn in first place at 27 percent among voters, with de Blasio gaining ground at 21 percent as Weiner’s numbers sank amid his latest sexting scandal.

"Nobody thinks former U.S. Rep. Anthony Weiner will pack it in, but 52 percent of likely Democratic primary voters wish he'd go away and 51 percent say they'd never vote for him," Carroll said.

Carroll indicated that Monday's ruling against the NYPD’s controversial stop-and-frisk policy appears to have had an effect on recent poll numbers. De Blasio has been outspoken in his opposition to the tactic.

"Two related issues which seem to resonate with Democratic voters are stop-and-frisk and the creation of an inspector general for the New York Police Department,” he said. “U.S. District Court Judge Shira Scheindlin did her part for the voters by appointing a federal monitor for the NYPD. If politicians follow the poll results too, the NYPD is going to get still another outside monitor."

Lest de Blasio get too comfortable with the latest numbers, the Quinnipiac poll notes that only 46 percent of Democratic primary voters say they will definitely vote for the same candidate they currently support. Sixteen percent say they are “unlikely” to change their mind, and 34 percent say they would likely pick another candidate in September.

Additionally, only 38 percent of de Blasio’s supporters are “definite,” compared to 42 percent in favor of Quinn and 54 percent voting for Thompson.