Short answer
Look for five signs. Decisions that should be made at their level keep coming up to you. Work waits for their sign-off. Their teams don’t work well with other departments. Strategic initiatives slow down once they reach that layer. And their best people are leaving. These signs warrant a closer look at skills, workload, decision rights and support before drawing conclusions about the managers involved.
The longer answer
Middle managers carry the heaviest load in most companies. They take direction from above, manage the work below and handle the friction with departments on either side. Many were promoted for being good at the work and never shown how to do this part.
Before you restructure or replace anyone, explore the skills and support your managers need. The free Magnificent Manager Assessment uses your responses to suggest two development priorities.