And if the depth isn't required (like it mostly hasn't been this year even when Garland went down)? A third consecutive year playing mostly for Casey. You've touched on the fact that Matty wouldn't want that, but I don't think the club would want it either. You've then got a bloke filling up a valuable spot on the list, who isn't being played, who has little improvement left in him, who will never again be part of our regular side.
If you're on the north side of 25 and you're a regular for Casey then your career has gone badly in the wrong direction. You're not depth, you're just a guy who is no longer good enough. Warnock fits this description, as do Bate and Dunn.