March 18...Begin free signings, trading etc.
April 1....Roster moves begin, players may be placed on DL if there by MLB team (or prediction is more than 30 days).
April 7.....Season begins be sure line ups are in and legal.
August 8...Minor Draft 6 rounds. Includes foreign signings since July 12 2020. If your drafted player does not sign you lose that pick. (if minor rosters are over the limit due to the draft, GMs have 48 hours to make adjustments)
August 15......ends trading period.
August 22....Ends FA signings.