Also you have to realize that Swanson is really only going to have 1 chance to cash in on a big deal if he proves to be the player we hope he is. He's going to be a FA after his age 28 season. He is less likely to sign away 2-3 years of FA like Teheran. A more likely scenario is either a bigger deal (which wouldn't be great for the Braves as you are then paying for non prime years) or either leaving via FA.
Fair point...especially if his hitting doesn't develop as he ages.