Expressing a desire to return to Boston would hardly undermine Roenicke. I think it is fairly obvious to anyone who looking at the situation objectively that Bloom would prefer that Cora manage if he does manage again, elsewhere. I accept Cora's statements at face value. I can understand why he would want to do something other than manage.
I hate to shatter your wishes but Cora isn't going to manage in Boston anytime soon.