This question often appears when organization moved to adopt agile from both sides: managers and developers.
Managers that have no practice of work with agile teams really could not know what to do and will spend their time and efforts without any positive results for software development. And even more -- this could create incorrect imagination for developers that managers are not necessary at all. Exactly this will decrease whole development performance.
From other side developers could do not understand that manager really do "his" work and that this work is really necessary for software development success. So it could born misunderstanding between manager and team and even lead to deeper conflicts. Again, this will decrease whole development performance.
Article What's a Manager to Do? introduce managers to area that manager of agile and self-organized team should work in.
I think this article will be helpful for both managers and developers.
