Practice roster sizes are set at 10 players, consisting of a minimum of 2 National players and a maximum of 8 International players. A minimum of 1 National player is required, and if the practice roster consists of 7 players, a minimum of 2 National players are required. Practice roster expansion occurs for 30 days coinciding with the period after the NFL roster cut down period increases the roster by five (5) players to a maximum of 15 in the fall. Starting in 2015 teams have the ability to choose when their 30 day expansion period begins within the league window, which in 2015 starts Sept. 5 and ends Nov. 8.
https://cfldb.ca/faq/rosters/