Yeah... that's a no-lose trade.
In a 12-team, start 4D league... there's only 48D in play.
Voynov is going to be a 35-40pt defenseman... but 35pts is fringe in a 48D league.
Green could be injured, could be 50pt+ again.
It's a great risk:
At worst, Green is wonky/injured again. You lose about 5pts of production... because you can find an emerging 30-35pt new guy every year.
At best, Green returns to 45 or 50 or even 55pts... and you've gained 10-20pts.