Things can change quickly in the world of talk radio.

On Tuesday, new ratings confirmed that Sportsradio 94.1 WIP's "Innes and Bruno Show," co-hosted by Josh Innes and Tony Bruno, is a hit among listeners, topping the much-coveted Men 25-54 demographic during the spring ratings period.

But the success apparently wasn't enough for Bruno, who announced he is leaving the show immediately and retiring from radio.

"The format and industry in general no longer provide me joy and satisfaction, even after reaching number one in p.m. drive in record time in my hometown," Bruno said in a statement posted on his website.

According to insiders at WIP, Bruno's decision came as a complete shock, and has led to speculation among listners that a frustrated Bruno had enough of Innes' style of radio.

Most of the speculation seems to be focused on an incident involving the treatment of a caller under the influence of drugs. But Bruno dismissed such rumors as the reason he decided to leave the show and WIP.

"I did not quit in haste because I "hated" or couldn't work with Josh Innes," Bruno said, noting in an email to management that he's not angry in any way, shape or form.

"In fact, I feel at peace knowing what I'm doing is right," Bruno wrote in the email. "I totally understand that my radio career in Philadelphia is over and can live with that. I have no desire to look for another radio or TV job."

While the two may never have actually fought, sources at WIP say the pair were never really close, a fact Innes alluded to on the air when he said, "We didn't talk a ton, maybe we didn't prep enough."

Bruno's surprise resignation caps off days of speculation over his absence from the show and the cadre of fill-in hosts asked to take his place. Tensions came to a head when a couple of tweets calling for Innes to be fired were re-tweeted and deleted by Tony Bruno's account over the weekend, but were later downplayed as an accident. Crossing Broad was the first to report about the tweets.

Still, Bruno did mention the polarization of social media and the industry in general as part of the reason he decided to step down.

"The modern world of radio and social media has sucked the fun out of doing this due to "factions" whose sole attempt is to provoke "wars" or have listeners "take sides" to anger or distract the process of doing radio every day," Bruno said.

Initially angry over management's decision to not talk about the situation on air, Innes disappeared for half an hour on Wednesday's show before returning to break the news of Bruno's departure. He was then joined on air by Operations Manager Andy Bloom, who spent an entire segment explaining the situation to surprised listeners.

Through Bloom, Bruno got one final dig in against his former employer, 97.5 The Fanatic "Missanelli will continue to lose to Josh no matter what, and that's the best part of this," Bloom said, reading an excerpt of an email sent to him by Bruno.

Now speculation shifts to who WIP will chose to replace Bruno to keep the successful show on track. On the air Wednesday, Innes made it clear he enjoyed the rapport he has with Jody McDonald, who currently hosts WIP 11 p.m. to 2 a.m.