David Shuster will definitely continue manning MSNBC's 4pm hour, a NBC source confirms to us, but that doesn't mean he'll quit what he's good at: primetime reporting. He'll continue filing reports for the NBC Nightly News and appearing on-air during MSNBC dayside, pulling double duty with the new role. But don't expect Shuster's hour block to be branded around him; we're told it'll remain the nondescript "MSNBC News Live," a la Andrea Mitchell's 1pm hour.

So why will Shuster be filling in at 4pm? For one, it's likely to save cash. While Shuster may get a small bump in pay for hosting the hour, it also means MSNBC doesn't have to shell out for another anchor's entire salary. (Just another example of 30 Rock filling MSNBC jobs with NBC News talent.) And also: Chris Matthews has been complaining about the lead-in numbers for his 5pm Hardball.

Shuster is a close friend of Matthews (unlike, say, David Gregory), having even sang at his wedding (he married Bloomberg's Julianna Goldman), and wouldn't have taken the gig if: 1) he didn't think he could deliver stronger lead-in numbers for Hardball; 2) Matthews hadn't given his blessing.

David Gregory's 6pm hour, meanwhile, was supposed to help Matthews' 7pm show, among other things. Not that the plan has been working out so well.

Also unlike Gregory: Producers generally like Shuster, we're told. Huh. They do make nice guys.

Shuster's new turn as a MSNBC anchor, meanwhile, is technically old news. He was supposed to get his own hour months ago, but then he made that unfortunate Chelsea Clinton "pimping" comment, which led to the Clinton campaign complaining, and a mini Shuster suspension.

Around the MSNBC newsrooms, staffers agree: Positioning Shuster in the anchor chair "makes good sense."