The value of a Business Analyst is asking “is this of value to the company?” Without someone to ensure the value of a project a project manager will take and complete what is given to them. It is often said that a Project Manager will deliver, on time, on budget and in scope, the perfect set of concrete shoes. The skillsets are complimentary as often a Business Analyst needs a project manager. Even analysis requires project management.
http://www.batimes.com/articles/the-value-of-a-high-performing-business-analyst.html
http://www.iiba.org//ba-connect/2013/oct/future-no-more-uncertain.aspx