I'm starting to agree with the poster that said that this announcement is setup by the coaches. It's never good when one of your top commits is wavering on his decision, but it would make sense if you think about it.
We picked up a new commit after every single loss this year. Now, we've had a silent couple of weeks and numbers are much tighter. What could drum up more excitement than a big JUCO signing day splash? If Lambert was solid, we really wouldn't be talking about him that much (See: Dontavius Blair). Now, all eyes are on his decision tomorrow, and the fan base will erupt with excitement if he chooses the Vols, as if he were a brand new commit. Since he's already technically committed, he also wouldn't be increasing the size of the class.
Several people have mentioned that the path to signing day would be fairly boring with Tennessee having an almost full class. Maybe this is a way to keep the fans engaged in the state of the football program. Who knows?