If I was Pacquiao sparring Castillo, I would be worried. You know he is going to practice against the ropes and Castillo has a great body attack. I think Castillo because it is sparring might do more damage than Cotto will in their actual fight because PAcquiao isn't going to be trying just to beat Castillo, but he will also want to practice the situations that benefit him least, and Castillo having you against the ropes is still a bad place to be.