In that article about Greene, Cameron said "We love him as a forward but equally we still haven’t put away the fact he can roll through the midfield as well. He is such a tough player to match-up up forward, that’s why he is so good up there – do you play a tall or do you play a small? That’s the great thing about Toby.”
My interpretation is: He's too good as a forward to play in the midfield.
Positive for Greene is that he's cheap, but the negatives are that he probably won't see much mid time, unfit, has trouble controlling his competitive spirit and is injury prone, hmmm.