Good point that is often forgotten. Trades are (almost never) "X for Y". Santana was going to play, no matter what. He's going to be a 3 to 4 WAR player, this year. Davis is probably a 2 WAR guy, or thereabouts, even with his power. He's dreadful defensively, and will always carry a low OBP. He's hit .244, .247, .247, and .245 the last 4 years, and doesn't walk a lot. We needed to make room for Domingo and logistically, moving Davis made the absolute most sense.