You mean other than the player not performing and not being able to trade them? Even if Span can only get a one year deal, he could probably get a deal more than we would be willing to pay with a team better than us. I'm sure the Nats would take him back if he couldn't find a multi-year deal in free agency. Even if we're using the Feldman/Arrieta example. At the time of that trade Arrieta was a 27 year old with a 5.50 ERA. I don't even think the Cubs thought he would basically turn into a Cy Young contender. I'm not really seeing a whole lot of players at positions of need that would be willing to take a one year value building deal anyways. We should be more focused on maximizing the value of Lind, Lucroy, Davis, Segura and maybe Braun instead of looking for one year value buys that we could maybe flip later.