I disagree with this. The project manager owns the schedule for the project. They are responsible for executing to it, its creation, and that it is maintained. In creating the schedule and defining activities from the WBS the project manager needs to work with members of the project team, functional leads, and other stakeholders to ensure that the schedule is achievable and meets organizational requirements. Team members will provide estimates on the activities, but the Project Manager is responsible for linking the activities together and executing to the schedule baseline.