If it's 2nd , 3rd , or 4th game of a series you can look at yesterdays box scores and then move the umpires in a clockwise direction. The umpire who was at 1b yesterday will be at hp today , the ump that was at hp yesterday will be at 3b today. ... but for 1st games of a series you'll need an odds service (sports options) to get earlier notifications , or you can use the mlb site , but they dont usually show them until about an hour before gametime so sports options is the way to go .