This is kind of odd: Seth Meyers is apparently one of three finalists to take over permanently for Regis Philbin on Live with Regis and Kelly. Yep, Live with Seth and Kelly could be a thing. He's guest hosted a number of times, including an upcoming stint for all five days of next week in the middle of sweeps. Could he be moving from late night to early mornings?
The other two candidates up for the job are former New York Giant Michael Strahan and singer Josh Groban, but apparently Meyers is the frontrunner. If he ends up being offered the job and then takes it, he'd presumably have to leave SNL — at least his job as head writer. He may still act as anchor of Weekend Update while handing the head writer reins over to someone else.
On the surface it seems like a weird move for him, but it could make a certain amount of sense. He's co-hosted the show enough that he clearly enjoys it and is comfortable with it. He doesn't act in too many movies, and he's primarily a writer outside of Weekend Update; a script of his called Alone For the Holidays is ramping up for production now. Presumably he could do the morning show gig while still writing scripts (and hosting Update) on the side. It'd certainly be a big change in tone and audience, but it would keep him on TV with a regular gig being funny while giving him enough free time to work on other projects.
And who would take over as head writer at SNL? The highest ranked writers under Meyers are Colin Jost and John Mulaney. Both receive Writing Supervisor credits in addition to their writing credits, which Seth Meyers also had before becoming co-head writer in 2006, so one of them would be a natural choice. Jost has been there longer — he started in the 2005-2006 season — so he may be the natural successor.
As for taking over on Update if he were to leave the show altogether, Mulaney has appeared at the Update desk a couple of times, although not at all in the last season, so it would seem like he'd at least be considered. Or it could be a castmember; a younger, underutilized player like Nasim Pedrad or Vanessa Bayer could be a fun choice.
In any case, it's all rumor and conjecture now. Seth could not get the job, or not want the job, and he could be back at SNL this September as head writer again. We'll see! But it sure is fun to speculate, right?