Actually the trade can be even as long as unmanage team gets younger players.

Thus trading for Beck and giving up a young prospect or draft pick for him to the unmanaged team would be both fair and making the unmanged team better for the next year. I.E. not lopsided.

Most managers that owned Beck would also make the same deal. A lopsided deal would require me to give up two young prospect or two draft picks.

Just my opinion. I've made about 10 unmanaged trades, while having about 15 rejected.