Actually, something no one addresses in either thread, but I found out the other day when I saw a walkover. The game is still played!
If you Watch Live, you will see a game played. It is your team against a team of Lucky Fans. So, the injury occurs because the game is played. After the game ends, the stats are then set to whatever the stats are for a walkover, but the injuries are carried over from the actual game. I would blame the rough fans from the team you played against!