Purchasing 4-Plex With Potentially Zero Current Lease Agreements

[Prag Patel]

I'm having issues deciphering what this means and hoping the BP community could help me with this, or whether I should just consult a lawyer.

Situation: Under contract to purchase a 4plex in Alabama. 2 units are currently vacant, and the other 2 are occupied. Upon contract agreement, I requested lease agreements, of which both expired summer of 2016 and the other expired this past summer. There are no clauses for month/month or any language stating the leases will automatically renew.

Question: Is this an issue? Am I putting myself in a position where I cannot evict or collect rent? 

Apologies if that has been covered in another thread (I did search but nothing exactly in this situation).