UPDATED: Rush Limbaugh is leaving WPHT

Rush Limbaugh -- the dominant force in conservative talk radio in America for more than two decades -- is leaving his long-time Philadelphia perch on 50,000-watt AM station WPHT, apparently for an unknown rival.

The dramatic move shakes up the Philly radio market -- and arguably the local political scene as well,. It's not clear how much the move was influenced by the national uproar over Limbaugh calling a Georgetown law student "a slut," which caused a number of major advertisers to jump ship.

WPHT confirmed the move just hours after a leading radio industry trade publication, Talkers magazine, reported that "the very hot rumor" out of Philly is that Limbaugh wa about to be yanked from his slot at 1210 on the AM dial -- to be replaced by Michael Smerconish, who now airs in the afternoon drive slot.

"Premiere recently notified WPHT they will be syndicating Rush Limbaugh on a new station in Philadelphia," CBS Radio said in a statement emailed to the Daily News. "As a result, we are pleased to be able to now showcase Michael, who is a well-known and acclaimed broadcaster in Philadelphia, in this new time period.

Smerconish said in the statement: "I have missed not having the chance to take WPHT callers in every hour of my program and am ecstatic that this will soon change. WPHT seeks to be live and local - no one is more local than me!"

Industry insiders were speculating that Limbaugh might not leave the Philadelphia airwaves for long, if at all. There are rumors, reported on Talkers and by Radio-Info, is that the new owner of WKDN-FM, 106.9 -- a Camden-based station that has carried Christian broadcasting -- may look to add Limbaugh as well as popular right-wing yakkers Glenn Beck and Sean Hannity, who've been off the air in Philadelphia since they were dropped by WPHT over a year ago.

But if Limbaugh did move to the lesser-known FM station, it would probably be a struggle to rebuild his Philadelphia audience -- especially in in a competition with the popular and locally based Smerconish.

And that could have a big political ramifications in Pennsylvania, considered a key battleground state in the 2012 presidential race.

The No. 1 listened-to radio talk host in America, Limbaugh's power is such that he's been considered the de facto leader of the Republican Party since the Bush administration ended in 2009. His right-wing screeds have rallied the tea party base of the GOP against President Obama -- and a prolonged absence or diminished presence in Philadelphia would leave a mark, politically.

Larry Ceisler, the local political pundit and PR consultant, said the rise of the moderate Smerconish may mean more politically than Limbaugh's move. Limbaugh core listeners, he noted. "are people who are going to be voting against Obama come hell or high water."

But in a stunning turn of events, Limbaugh has been fighting to save his show in recent weeks, ever since he lashed out at 30-year-old Georgetown law student and women's rights activist Sandra Fluke, calling her "a slut" for advocating wider health-insurance coverage of contraception.

A subsequent apology hasn't stopped a whopping 67 companies -- spurred on by liberal activists and a social media crusade -- to drop all advertising on Limbaugh's program. Because of the complicated ways that radio advertising is sold, the fallout from the Limbaugh controversy has spread to other talk shows -- especially hard-core conservatives like Beck and Michael Savage -- and reportedly even some music programing. Locally, some advertisers like the Philadelphia Orchestra instructed WPHT not to air their ads during Limbaugh's program, from noon to 3 p.m.

Despite the advertising bloodbath, only a few smaller stations -- in places like Hilo, Hawaii, and Pittsfield, Mass. -- have dropped Limbaugh altogether.

But at WPHT, Limbaugh has increasingly become the odd man as the station has moved largely to a "live and local" format. Smerconish -- whose live, nationally syndicated program airs during the same time slot as Limbaugh -- had created a complicated fit here. He has been broadcasting a locally oriented live hour from 3-4 p.m., and then the station carried his syndicated three-hour show on tape.

Smerconish will be a major change in tone from the bombastic and unfailingly conservative Limbaugh. Although he was once a local GOP official and has conservative views on some issues like racial profiling, Smerconish backed Obama in 2008 and has become a registered independent.