By Mike Dunn

PHILADELPHIA (CBS) — A former spokesman for Mayor Nutter, who had considered running for mayor as a Republican next year, now says that if he runs he’ll join the crowded Democratic field.

Doug Oliver, who was spokesman for Mayor Nutter during Nutter’s first term and is now a vice president at the Philadelphia Gas Works, has formed an exploratory committee to look at possibly succeeding Nutter.

Oliver originally looked at running for the Republican nomination — in all likelihood, to avoid the crowded Democratic field.

But now Oliver, 40, says if he runs, it will be as a Democrat, given the party’s 8-1 registration advantage over the GOP.

“Ultimately we did not want to make people choose between their party and our ideas,” he tells KYW Newsradio.

Oliver says he’ll announce within two months whether he is actually running for mayor. His announcement of an exploratory committee comes one day before two other Democrats — state senator Anthony Williams and former district attorney Lynne Abraham — are expected to formally announce that they will seek their party’s nomination next May.

Two others announced earlier: former city solicitor Ken Trujillo, and the former head of the Philadelphia Redevelopment Authority, Terry Gillen.

Yesterday, city controller Alan Butkovitz announced he will not run for mayor in 2015.