We are going to be hiring a additional employee later this year. Is there a way I can add the compensation expenses for this employee to my budget without knowing who the person is yet?

Yes, HCP allows you to plan for a To Be Hired  (TBH) employee. From the Monthly Pay Rate tab of the Manage Existing Employees and Job Codes task list,, you can right click and select Manage Employee -> Add TBH.  Select the DeptID (defaults to value in the right-clicked row), TBH #, Job Code, Monthly Pay Rate, Start Year, Month and End Year /Month and any  Comments.

Once the TBH is added you will need to add a TBH Distribution by right-clicking over the newlTBH on the Monthly Pay Rate tab and selecting Manage TBH -> Add TBH Distribution. 

 Once the actual employee is hired and actual salary expenses are loaded to CalPlanning for that employee from PPS during the month end close, you can then assign that employee to the To Be Hired employee compensation plan.