Offer manager field does not appear to be an option to use in a report

Summary

Offer manager field does not appear to be an option to use in a report

Content

I have a report that lists offers accepted over a period. I am trying to edit the report to include the Manager field that displays on the New Offer page. When I edit the report and navigate to the Select Fields and Parameters page, I select the Offer tab and review the fields listed. Manager is not one of the available fields even though it's a field that we can select when we create a job offer.  How can I include the Manager