Jessica Taubner, an aide to City Councilor At-Large Ayanna Pressley, is strongly considering a run for departing City Councilor John Tobin's seat.

The Jamaica Plain resident is a former researcher with the Legislature's Health Care Financing Committee. She also worked on mayoral campaigns of Michael Flaherty and Sam Yoon last fall.

The field of candidates currently includes Matt O'Malley, who has run twice of City Council, and Jim Hennigan, brother of former City Councilor Maura Hennigan.

David Isberg, Tobin's chief of staff, is also reportedly considering a run.

Tobin, elected to the council in 2002, is stepping down in August to take a high-level post at Northeastern University. A special election is likely to take place this fall.

UPDATE: Taubner and Isberg aren't running. Still mulling a decision is Valerie Frias, a former state Senate aide who has also worked for the Massachusetts Taxpayers Foundation.