It might be helpful to look at a 4-1 in this context. First, unless Hendry does something dumb, like signing Roberts to an extension, the Cubs are going to reap two fairly high draft choices for Roberts when he departs as a free agent. Those are draft choices that the Orioles won't get. It seems fair to "replace" those for the Orioles. That's two players. We can debate how valuable those guys should be. Then, you're down to how much is two years of Roberts worth. Two players seems reasonable. Again, we can debate how valuable those two guys ought to be.