Presumably because they believe he can play himself back into form and contribute in the mean-time.He also has (at least in theory) a skillset that not a lot of others have. The combination of genuine clearance winning midfielder at his size and good to very good kick of the footy continues to seduce everyone.
Every coach he's had has regarded him as pretty much an auto in when fit so he obviously says and does all the right things on a week to week basis which is an underrated quality in and of itself but I think he's pretty well cooked.
Why he's being brought back in these circumstances is completely beyond me
I feel there's also quite a bit of residual resentment over the clear policy of the past couple of seasons that only one of he and Langford could play at a time. As Wearybomber would put it, that's hardly his fault - and thankfully Langford remains in.