Butch Forster, 59, the general manager of sports radio WIP 610-AM for the last decade was fired without warning Thursday, according to a station source.

Tom Bigby, WIP program director since 1986, had no comment on the firing. It is not believed that Bigby is a contender for Forster's position.

According to the station source, Forster's departure appears to be a restructuring of the entire Philadelphia Infinity network, which includes WOGL 98.1-FM, WYSP 94.1-FM, WPHT 1210-AM, and KYW 1060-AM.  There are 180 Infinity stations around the country.

Dana McClintock, spokesperson for Viacom, which owns Infinity Broadcasting could not be reached for comment.

Viacom made the news a few days ago when company president and chief operating officer Mel Karmazin announced Thursday he will stay at the media giant for another three years, ending months of speculation about his future and sending the company's stock up sharply.

WIP, one of the top stations in the 25-54 male demographic, placed 10th overall in the last Arbitron ratings for ages 12 and above.