Mock Protected Parent Method When the Parent is in a Different Package and the Child Class is Abstract

I need to mock a protected method in the parent class of my class under test but the parent class is in a different package. I thought that the solution would be to use PowerMockito.spy() but I cannot instantiate the type Child because it is abstract. There's gotta be a solution for this issue without refactoring.

Here's the Dependencies.

        <dependency org="org.powermock" name="powermock-core" rev="1.6.4"/>
        <dependency org="org.powermock" name="powermock-module-junit4" rev="1.6.4"/>
        <dependency org="org.powermock" name="powermock-api-mockito" rev="1.6.4"/> 

This is legacy code so I cannot refactor, but here's the simplified code.

Parent.java

package parent;

public class Parent {

    // Want to mock this protected parent method from different package
    protected String foo() {

        String someValue = null;

        // Logic setting someValue

        return someValue;
    }
}

Child.java

package child;

import parent.Parent;

public abstract class Child extends Parent {

    String fooString = null;

    public String boo() {

        this.fooString = this.foo();

        String booString = null;

        // Logic setting booString

        return booString;
    }
}