Just search 'Alabama College Football Rosters' and add the date you're looking for at the end.
Current NFL rosters after training camp are 53.
http://www.huskers.com/SportSelect.dbml?spid=22&spsid=4&db_oem_id=100 Top right..there's a pull down menu for year..
Go to Gatorzone.com for rosters going back to 1995
Call their sports information director.
The Pro Football Reference website and the Football Database have full rosters.