That xBA is silly. The play Mullins made was a .560 xBA, so if Palacios hit that same ball 100 times he would probably have a batting average of .010 and an xBA of .560.
Who do you replace him with? Cowser has a .580 OPS in May and .330 so far in June. All the bad luck talk is just that, there have been no results for over a month now.