No joke: NBC a good bet to bump Jay Leno for Jimmy Fallon

Jay Leno had to know the head honchos at NBC were gunning for him when he told the following joke Monday night: “You know the whole legend of St. Patrick, right?” he asked the audience in his opening monologue. “St. Patrick drove all the snakes out of Ireland — and then they came to the United States and became NBC executives.”

The harsh humor directed at the guys who hold his fate in their hands is just the latest sign that the star and his bosses pretty much detest one another. So, is Jay really being replaced by Jimmy Fallon? Is “The Tonight Show” going to leave Los Angeles (a.k.a. Burbank) and move to New York City, where it was born back in the days of Steve Allen? Is this going to be another ill-conceived idea cooked up in NBC’s corporate suite that will cost the network even more viewers? We will find out as the latest Machiavellian twist in the serious business of late-hours TV comedy unfolds.

Until Jay Leno took over NBC’s “Tonight Show” in 1992, late-night television was a realm dominated by one undisputed king, Johnny Carson. Then the unending wars of succession began.

David Letterman had held down the after-hours slot following Carson, biding his time in the hope of moving to 11:30 when Johnny finally called it quits. When Leno grabbed the crown instead, Letterman moved to CBS and promptly beat his rival in the ratings game — at least for a while.

That old rivalry between Carson’s would-be heirs seems like an orderly duel compared with the current pig pile of joke-slinging hosts. A revolving lineup of ambitious comedians on several networks has been taking a shot at stealing pieces of the nocturnal audience, scrambling the ratings equation in the process. One of the most successful of the bunch is Jimmy Kimmel on ABC. The word is that his show was moved up to directly take on “The Tonight Show.” Despite the fact Leno still tops the ratings, inside sources at NBC say it is certain the 62-year-old veteran will be replaced in 2014 by the youngest of the young upstarts, 38-year-old Fallon, the current host of NBC’s “Late Night.”

Network execs are betting their Jimmy will do a better job holding younger viewers in a face-off with ABC’s Jimmy. Of course, an earlier gaggle of programming gurus notoriously tried this before. In 2009, “The Tonight Show” was awarded to the then-host of “Late Night,” Conan O’Brien, and Leno was given the consolation prize of a show at 10 p.m. That did not work out well. Within months, Jay was back and O’Brien was cast into the comedy wilderness until he landed a gig with TBS.

Is Leno really gone this time? Stay tuned.