Jay Leno, who pretty much rolled over when Comcast came through the "Tonight" offices with a budgetary meat cleaver last week, may have a larger concern than saving a few jobs - he may be worried about his own. Check out this shrewd column in the L.A. Times by Joe Flint - himself a shrewd observer of the late night scene. He posits that Jay, with a year to go on his contract, may be fighting a rear guard action against a company thinking about installing Jimmy Fallon as the next host of "Tonight." NBC has certainly considered a Falllon-to-"Tonight" move for years - former NBC chief Jeff Zucker thought Fallon was ready to take over "Tonight" even when he was about to leave the company - but there have been a couple of minor hitches: Jay's "Tonight" has done pretty well, and whom to replace Fallon with at "Late Night?" And consider the viewer revolt when Jay was dumped the last time around - the reason I think Jay's still in a pretty solid position of power. But with the Jimmy Kimmel to 11:35 arriving in January, Kimmel's eventual arrival at 11:35 may be a foregone conclusion. Little wonder Jay's worried?