Somebody is taking advantage of the fact you're a newbie. Never give up an elite player for 2 or 3 lesser ones. You could combine the points those other guys get weekly, and still not equal AJs. More importantly, you'd be using 3 roster spots instead of only 1.
If you need help at RB, post your complete roster and ask for trade ideas. If you have a lot of depth at WR, it's possible Green could be part of a trade, but you'd be much better off doing a 1-1 deal where you get an elite RB in return. And yes, I'm talking about guys like Gurley and Hunt .