Is it possible to make time sheet entry mandatory for an employee who is resource on a project?

Summary:

We are working in a projectized environment. Is it possible to make OTL entry for previous periods mandatory for employees who have been assigned to projects?

The use case : An employee tries to enter his/ her time sheet on the project for current week without entering time sheet for last week. System should not be allowing the user to complete/ submit time sheet without adding hours for last week.

If the above is possible then for a new employee who has been assigned to a project, how would be the first entry?