You might want to ask the commish directly about this. I do know that PB likes to let managers have the options a real manager has, and that means lots of leeway position-wise. I think that with a small sample of playing time, however, that Walker will be worse than his actual stats. I have not checked but I'd guess his PB fielding is 1.0 or below. That means not only a poor percentage, but HORRIBLE range and few double plays. Yes he'll give offense, but unlike many other baseball games, the tradeoff will be costly. If you find out more please post it.