He might want an opt out because it is Pitt and he doesn't want to stay there for another 5 years with a crap team.
but he is an interesting contract case. He is controlled through his prime (30), so he is realistically going to get one big payday and then probably some middling ones to finish his career. But why would a team want to give him an opt out when they already control him til he is 30. If I am buying you arb years out, then a team is going to want a team option for at least his first FA year to limit their risk.