Sports on Earth (which has taken a serious quality hit of late but is still quite good) has a very nice article on the ticking clock some MLBers face with regards to the HOF, based purely off past voting histories.
The article’s surprisingly depressing on a couple of Hall cases. Jeff Bagwell is project to go into the HOF, but the authors thinks Bags might have a delay until 2020. That’s based largely on the assumption that three-man classes will be rare, and that a four-man class will be totally unheard of. I think even the HOF voters will have to accept three-man classes for a few years just to clear the logjam.
I also think Piazza sails in next year; I wouldn’t even put a “worst case” scenario then. It’ll depend on if Biggio gets in, but I think he will.