Why Some Games off the Board in Survivor?

Does anyone know why some games are Off the Board on the Streak Survivor Contest Pick section? 

I notice as I cap my games that many, many times a stron play I cap is off the Board.  So I started tracking them to see if there is a correlation and have some intersting results, but want to see if anyone knows why some games are removed?  

I think that when one team gets too much of a favorite they take it down like Minny 75% with Money Leaders so it comes down. It seems like into 65% is ok but not much above that. As I said I don't know this for a fact but it sure happens a lot from what I noticed.  

Now I see Philly at 81% & still up so I don't know?  

It seems after I get done capping my college basketball games and bet the, I then go in to make streak survivor pick and the top games I want to pick are off the board, and usually there are not that many off the board, I have been doing pretty good then going back and upping my bets on the games that are off