Because the last scrimmage for the season happens after the end of season batch run, so the draftees will have already been drafted before the game. Even though the game takes place after the end of season batch, it still is considered to be in the previous season as the new season starts with a new week. End of season batch processing normally takes place on a Sunday/Monday, so after everything completes on Tuesday we are still technically waiting for the week to complete before the next season starts.
Actually, "drafted in season 2" means he was picked in the draft that took place in the
end of season 2, so there is absolutely no way he played in season 1
"I don't know half of you half as well as I should like; and I like less than half of you half as well as you deserve."