What is the role of the project manager in an Agile project that has a Product Owner and a Scrum master on the team

Question

In my view, a project manager assigned to an Agile project can fill the role of Scrum Master/Product Owner/Team member according to his/her inclination, experience, background, skills, etc. 

But assigned to a project where these roles have already been filled? I believe the value add is in coordination (eg. virtual teams), internal/external communications, customer relationship (supporting PO), contract management, risk management, quality management...

Comments, please?

Answer 1

I imagine a PM might be particularly useful in coordinating interactions between teams participating in a Scrum of Scrums, particularly if those teams aren't co-located. In SCRUM, you could say that Scrum Master could fix as project manager

Answer 2

In SCRUM, you could say that Scrum Master could fix as project manager.