Been probing around the radio industry for the last two weeks, attempting to get a grip on what’s going to happen to one of the most popular sports talk radio shows in the country, Mike and the Mad Dog (NYC radio partners for 18 years, and the show is simulcast on the YES Network). The Watchdog, Neil Best, has been tracking this story intently. Among the rumors we’re hearing that are floating about the transom of the industry:

* Mad Dog Russo’s primary backup plan, should this tandem split up in July - as Francesa hinted at last week - is Sirius radio, a source said. The same source said Russo has connections there.

* According to a source, Francesa, feeling empowered by mild success with his Sunday night sports show, Mike’d Up, started to explore further TV options earlier this spring when the relationship between the two hosts frayed. Francesa was a CBS Sports analyst in the late 1980s and according to his wikipedia, in the running for the Monday Night Football gig that eventually went to Dennis Miller in 2000.

* One popular theory is that WFAN would keep one host, should the pair decide the partnership is untenable. Sources feel this would be a disaster for the show, since the reason for the pair’s success is that the supremely arrogant Francesa brings a modicum of credibility to the airwaves (boasting about his cozy relationship with Bill Parcells, for instance), and plays well against Russo’s silly, fanboy, gibberish antics.

* Though nobody at ESPN will confirm this, the WWL is reportedly thrilled with this development, because it opens the door for Mike Tirico, Scott Van Pelt and the insufferable Michael Kay to put a dent in the sizable ratings stranglehold Mike & the Mad Dog have on NYC’s daytime talk radio.