Short answer, bad trades.
Chapman, although being reported as being in better shape (injury wise) this year than last, he has lost a bit from his game. There is a thread over on the Geelong board discussing Chappy if you would like a bit more insight in how is traveling.
As for the Ruck trade, Mumford will average at least 10-20 points more and will have the odd 120pt game. I can see more upside to Mummy, although why he can't get on the park at the moment is frustrating for some but he will come good eventually. I'd suggest Nic Nat who is in good form and would be another POD, Kreuz has started good but got smashed against a good ruck duo last week. FWIW, I went Mumford > Kreuz last week, Sandi was in reach but I needed the POD.
Thanks for your advice.
I have decided to trade out Mumford for Naitinui cause it gives me $155,000 cash left in the cap. As for Kennedy, he is getting another lifeline...