I hope the Red Sox are involved in this. I would trade Swilhart for Zimmerman, no sweat at all. If the Red Sox don't resign Zimmerman, they collect the compensation pick. So, in that scenario, they trade Swilhart for one year of Zimmerman and a compensation pick. Swilhart might be great, he might be average, he might be a bust. Likewise, the compensation pick for Zimmerman might yield a great player, average one, or bust.
I wouldn't trade Betts, the Red Sox are relying on him to be an integral part of their 2015 offense, whereas Swilhart isn't quite ready. Moreover, as the minor league numbers suggest, I think Betts has more upside with the bat.