Welcome back RotoBallers, to another edition of the fantasy baseball waiver wire rankings for Week 19 -- July 31 through August 6. The MLB trade deadline is Monday, and we will see more significant roster shakeups, such as the Rangers acquiring ace Max Scherzer from the Mets on Saturday. Many roles could change or open up as teams make roster moves geared toward a World Series run. More top prospects are being called up to the big leagues, and some are producing for fantasy managers immediately....