Sam Katz can't help himself. If there is a race for mayor in Philadelphia, his instinct is to jump in.

He has made the leap thrice, but will tell you he's been tempted and passed as many times.

It comes as no surprise, then, to hear that the lure is still there, and all the more attractive with Wednesday's sudden withdrawal of Ken Trujillo from the May 19 Democratic primary. So much so, Katz said Thursday, that he's giving a fourth run serious consideration.

"I need to take a couple days to really talk about it with my wife," Katz said. "That is all I really want to say about it right now."

Don't imagine this is a reflex response to Trujillo's decision.

Katz's interest has been long-standing, enough for him to have met with City Council President Darrell L. Clarke on Tuesday - the day before Trujillo's unexpected withdrawal - to talk big-picture issues. Katz declined to go deep into details of what he described as a private conversation, but acknowledged that it was part of his process of deciding whether to run.

"The most important part of the meeting from my perspective was the conversation about where the city was going," Katz said, "what are the big things that, under the current political system, the mayor and City Council can collaborate on and accomplish."

He made a passing allusion to his age, 65.

"Though it has been long been my aspiration to be the mayor, I'm at a stage in my life where just to be mayor wouldn't be important," he said. "It would only be valuable if the outcome was impactful to the city's future."

He also acknowledged there was a hole in his resumé when it came to Council.

"I am probably one of the few people in Philadelphia political life who knows very little about City Council," he said. "I have not spent time working for anyone in it. I don't go to Council meetings. I don't know the players. ... I don't know Darrell that well. That was the nature of what I was interested in."

For the moment, there are three declared candidates for the Democratic mayoral nomination - State Sen. Anthony H. Williams, former District Attorney Lynne M. Abraham, and former Common Pleas Judge Nelson Diaz. Two more - Doug Oliver, Mayor Nutter's former spokesman, and former State Sen. T. Milton Street Sr. - have said they will announce in February.

Katz has been a public-finance consultant and more recently a maker of documentary films on Philadelphia history; he also chaired the state board that oversees the city's finances.

He ran for mayor in the past as a Republican. He has ruled the GOP out if he were to run again. He declined Thursday to say whether he would run as a Democrat or an independent if he runs this year.

His political party affiliation has been in flux for the last eight years. He was the Republican Party's nominee for mayor in 1999 (when he lost by a few thousand votes to John F. Street) and 2003 (when Street beat him by a wider margin), having also lost in the GOP primary in 1991. Katz switched to independent in April 2007, and back to Republican seven months later. He became a Democrat in March 2008 and then went back to Republican in January 2012. He remains a Republican for now.

As it happens, an independent candidate faces a lower bar than usual to get on the 2015 ballot.

Democratic and Republican candidates must collect signatures on nomination petitions from 1,000 registered voters in their party who reside in Philadelphia.

An independent candidate's signature goal is set at 2 percent of the last top vote-receiving candidate in a citywide election. The last citywide race was a low-profile one: Ed Neilson's successful bid for a Council at-large seat, a vacancy that was filled in a special election concurrent with the 2014 gubernatorial primary.

Neilson received 66,204 votes in that race. An independent candidate this year would need signatures equal to 2 percent of that tally, or 1,325.

Feb. 17 is the first day for mayoral candidates to circulate nomination petitions. Katz's intentions should be known by then. 215-854-2594