Baseball's always full of uncertainty... roles change all the time, and the smart fantasy manager has to have a good sense of this to take advantage of trades and whatnot, especially in deep leagues.
So make a specific prediction (date) that certain events will happen... it'll be pretty awesome if you end up being right, eh?
How long until...
Daniel Bard staying in the rotation
Chone Figgins is traded or released
Brad Eldred loses his DH role
Hector Santiago loses his closer role
Scott Downs loses his closer role
Chris Parmelee loses his starting role or gets sent to AAA
Peter Bourjos or Vernon Wells is traded
Aceves loses his closer role
Brandon League is traded
Jesus Montero becomes the full-time catcher (or if you don't think he will, when he'll reach 20 games there)
Michael Taylor gets a starting role
Kila Kaaihue keeps getting regular starts at 1B
Dayan Viciedo is demoted or becomes a backup
Eric Thames is demoted/traded and/or Travis Snider is called up
Jack Hannahan loses his starting role to Chisenhall