Since most of my readers play in deep N.L. or A.L.-only keeper leagues, I get a lot of questions from my readers about whether or not such and such a player is going to get traded. This applies mostly to owners who play in leagues where you lose a player traded to the "other" league. However, it also matters in leagues where you keep the stats of a player traded to the "other" league but lose that player after this season. Losing Drew Pomeranz to the National League can sting just as much in a keeper league as losing Ubaldo Jimenez.
The most consistent advice I can give about the deadline is that most players that are rumored to be dealt don't get dealt. This is particularly true of mid-July rumors. It is very rare that a player is moved in mid-July, and while the rumor mill could possibly be some indication that a player is on the block, that doesn't mean he'll be moved.
It isn't in the best interest of a front office to definitively indicate that a player will be traded on July 31. Why damage your leverage with other Major League front offices by saying that a player has to be traded?
Turning this back to Roto, it is best to hang on to a player who will "definitely" be traded. If you flipped Ryan Ludwick for pennies on the dollar on Saturday, you lost out on Sunday. On the other hand, it probably doesn't behoove you to trade for a player involved in rumors. If you flipped for Derrek Lee, all you got was a pile of FAAB to spend on the limited number of N.L. imports.
One good thing about the proliferation of information is that if a player isn't mentioned in a rumor, there's an excellent chance he won't be moved. Gone are the days of not hearing about a possible trade until you read about it in the newspaper the following day. If a player's going to get traded, you'll at least start hearing about the possibility on Twitter almost right away.
I generally will treat the possibility of a player being traded as a reality once I start seeing multiple rumors from trusted sources that start outlining specific destinations. B.J. Upton and Kyle Farnsworth were examples of players who I didn't think would be traded because the rumors were vague and - ultimately - unfounded.
Your goal in Rotisserie is to maximize your value. You don't want to get left holding the bag on a player traded out but what's worse is to give that player away to a competitor. Hang tight. If you lose out, you still did the right thing.