The Product Owner does not have to attend the Daily Scrums and should not 'participate' but it's a good idea to attend to stay informed of the progress. The other option is to check the task board or Sprint board which is usually a large
board in the project room and displays the Sprint Backlog with extra information. There's no team leaders in Scrum; we don't ask for push reports and the Scrum Master doesn't have to know much about the progress.