When a team does not have at least 3 players active in the lineup for a game, they forfeit the game and you win by a 50-0 score. The match viewer will show your team showing up and playing the lucky fans, but that does not actually count for the minutes your players receive for training purposes, or for player stats.
When your team wins by forfeit, your players will gain 36 minutes if they were set as starter in the lineup, 10 minutes if they were set at backup, and 2 minutes if they were set as reserve. Any positions that were left blank on the lineup will receive 0 minutes for that position.