Jeffries at 6 is less of a worry than Chev at 4 imo. My heart sank a little when I saw who he'd given the 1-5 shirts to.
Not only is Chev nowhere near good enough to be a starting centre, but if he does play 4 then Kear will also suffer just by playing outside the guy. The only ball he will ever get will be from coming inside to help out at the ptb.
I guess the pre season games will give us some kind of idea, but I would much prefer a back line of BK, Kear, Lulia, Purtell and Ainscough. I'd even take Platt at centre before Walker.