The way I see it, the problem with our 3 key defenders in Thursfield, Moore and McGuane is that they're all around the same height and weight (190-191cm - 84-86kg), which is a bit too short and lightweight for a key defender. Ideally a CHB and FB should be a minimum of around 195cm-94kg, which leaves those 3 more ideally suited to the opposition's 3rd tall forward. So while it may be valuable to keep two or possibly all three on our list for backup due to injury,we cannot afford to play more than one in the same side.Choosing who is the most tradeable though is difficult, as their respective form has fluctuated considerably. Will was very versatile in his early years, being able to play on the likes of Riewoldt, O'Loughlin, and Milne. But his form has been up and down since his knee reco. Ditto Moore who had a great season last year stopping the likes of Buddy, Fev, and Brown,has struggled with a shoulder this year and his form has suffered. A key flaw with all of them is that none are very penetrating kicks either.